Good luck to your DD, whether she decides to do the presentation or not!

Sorry about the essay in response.
There are some amazing suggestions here, but I agree it sounds like she is informed and could tackle this amazingly. It's a HUGE topic, so keeping it focused will probably be a little hard.
Maybe just aim to encourage a little bit of discussion/thought around the subject rather than try to cover everything? If presenting, I'd second the suggestion she is crystal clear in her definitions of sex and gender from the onset, especially if she is using Posie's lightshow and the controversy around the dictionary definition of the word "woman."
You can even consider framing the discussion around when there is a clash around "sex" and "gender identity" in the more abstract than turn it into different "sides"? Like, when is SEX actually incredibly important?
I'd advise not to get bogged down by any arguments that conflate trans with intersex conditions, or who is "true trans" or "fake trans", because they are irrelevant to the self-ID debate. As bowlofbabelfish always asks: "Can humans change biological sex?" (No, no they cannot, and certainly not by just loudly declaring that they "are" the opposite sex).
These questions from Rebecca Reilly-Cooper are important, because they highlight the work the category "female" and "woman" do. rebeccarc.com/posts/
Some basic questions about sex and gender for progressives
1. Do you believe that being born with the kind of body that has the potential to gestate children – a body with a uterus, ovaries, and a vagina – is of any political significance? Does having that kind of body have any bearing on a person’s likely opportunities and outcomes?
2. Do you believe that people born with those kinds of bodies have historically been subject to any distinct forms of injustice, oppression, exploitation or discrimination? Have they historically been subordinated to the people with penises and testes?
3. Do you believe that people born with those kinds of bodies continue to be subject to any distinct forms of injustice, oppression, exploitation or discrimination?
4. Do you believe that people born with those kinds of bodies often suffer physical and sexual violence, abuse and harassment perpetrated by the people with penises and testes?
5. Do you believe that people born with those kinds of bodies ought to have a label with which to define themselves? Does our language need a word to refer to the people with uteruses and ovaries?
6. Do you believe that people born with those kinds of bodies have a right to organise politically around their shared experiences, and to campaign and work for policies to secure their own interests?
7. Do you believe that people born with those kinds of bodies have a right to associate freely with other people with those kinds of bodies, and to have some separate spaces for their safety, privacy and dignity? Do people with those kinds of bodies have a right to some spaces where people with penises and testes are not permitted to enter?
8. Do you believe that people born with those kinds of bodies sometimes have a right to policies and resources designated towards rectifying their historical and continued marginalisation and oppression?
If your answer to any of these questions is “yes”, you should reject the ideology of gender identity, and policy proposals based on that ideology such as the self-declaration of legal gender.
I think your DD's instinct around sports is good. It's visual (you can have pictures of the athletes in question), and any young woman dreaming of athletic success should understand it.
If your DD hasn't spent time on Fair Play for Women, that site is a treasure trove of information on the self-ID issue.
fairplayforwomen.com/sport/
She could pull up some basics about the differences in male and female physiology (extending FAR BEYOND just hormones), show figures of the gaps between male vs female records in sports, and if she had a favourite female record holder in (for example) the Olympics, she could argue that this woman would never have seen success or recognition if there was no female-only category; a mediocre man would have beat the woman every time.
To look at an anecdote, one could perhaps just focus on a high-profile example?
There was significant discussion around Laurel Hubbard (MtF weightlifter from NZ) around the time of the Commonwealth Games. Even some of the people supporting Hubbard's right to compete understood it was impossible for the females to win, but said "them's the rules" so technically it's allowed. So the question is whether the rules are actually fair to women?
Hannah Mouncey is also one to look at, because of legitimate safety concerns. Presenting it from "both sides" can be hard, but you can pull up Hannah Mouncey's own opinions and critique them?
www.theguardian.com/sport/2018/sep/03/afls-trans-participation-policy-sets-a-dangerous-precedent-for-women
Here commentary around Laurel Hubbard and the Commonwealth Games:
www.theaustralian.com.au/sport/disquiet-over-transgender-weightlifter-laurel-hubbard/news-story/12f7647ddbe54aceef2241e80c9e05a3?nk=d91a28cc2e262a8a1a27faf2fd813901-1548757818
And a professor of physiology on the unfairness of this:
www.stuff.co.nz/sport/other-sports/99434993/professor-of-physiology-says-trans-athlete-has-advantage-in-speed-and-power
It may also be worth quoting Renee Richards (one of the first MtF transsexuals who played in women's sports):
Despite all this, Richards has expressed ambivalence about her legacy. She continues to take pride in being “the first one who stood up for the rights of transsexuals.” But she also mused, “Maybe in the last analysis, maybe not even I should have been allowed to play on the women’s tour. Maybe I should have knuckled under and said, ‘That’s one thing I can’t have as my newfound right in being a woman.’ I think transsexuals have every right to play, but maybe not at the professional level, because it’s not a level playing field.” She opposes the International Olympic Committee’s ruling in 2004 that transgender people can compete after they’ve had surgery and two years of hormonal therapy.
The science of distinguishing men from women in sports remains unsettled. And Richards has come to believe that her past as a man did provide her advantages over competitors. “Having lived for the past 30 years, I know if I’d had surgery at the age of 22, and then at 24 went on the tour, no genetic woman in the world would have been able to come close to me. And so I’ve reconsidered my opinion.” She adds, “There is one thing that a transsexual woman unfortunately cannot expect to be allowed to do, and that is to play professional sports in her chosen field. She can get married, live as woman, do all of those other things, and no one should ever be allowed to take them away from her. But this limitation—that’s just life. I know because I lived it.”
Slate article, archived here:
<a class="break-all" href="https://web.archive.org/web/20150208113015/www.slate.com/articles/sports/sports_nut/2012/10/jewish_jocks_and_ren_e_richards_the_life_of_the_transsexual_tennis_legend.2.html" rel="nofollow" target="_blank">web.archive.org/web/20150208113015/www.slate.com/articles/sports/sports_nut/2012/10/jewish_jocks_and_ren_e_richards_the_life_of_the_transsexual_tennis_legend.2.html
I would say the other instinctive issue is prisons. The classic case there is Karen White. But be aware that the common argument against it is NAMALT (not all males are like that, whether trans or not), and you may need to drill into the facts of male-pattern violence, plus it could be hard to talk about sexual assault in class. Or another angle could be healthcare, and here it's quite easy to illustrate "both sides" as it were. Because you can say that trans people may find it intrusive to be asked about their biological sex, but there are SO many reasons that a healthcare professional will need to know the basic facts of anatomy and physiology that are related to one's actual reproductive system plus any "cross-sex" interventions.
In any case the focus from the feminist perspective is about fairness for women, and how essential it is for females to be allowed to have their own category based on the actual biological reality of sex. It's about protecting the most vulnerable women, risk-management, and allowing women something of their own where their interests are prioritized instead of everyone else's.
It's really about a conflict of rights, how to balance these, and letting females retain autonomy over their spaces and advocate for their own needs. Frankly, it's my opinion that we can't do that if the female identity is being questioned and re-defined as simply a nebulous "feeling." This should be in transmen's interests as well (and "assigned female at birth nonbinary folks"), given that they will share the biology of females who call themselves women, and have certain specific needs. If looking at language, I think anything that obfuscates the reality of biology is profoundly unhelpful and makes it harder to focus on the real needs of females as a sex.