With the greatest respect, raspberry, I know you are doing your best, but the guidance from GG does NOT allow for girls to be comfortable and respected. It's just not possible for them to allow transgirls to share with biological girls and not tell parents, and at the same time allow girls to be comfortable and respected. Any time a child's sex is a secret (from girls or from parents) there is a risk of another child being uncomfortable and disrespected.
Likewise the guidance does NOT allow for trans children to be safe. Again, if their sex is a secret, this is something a predator can hold against them. You cannot say "it's unlikely" or "nobody would do that" or "everyone knows they are trans". The guidance does NOT allow for "everyone knowing they are trans".
So either you are not upholding the guidance (if you ask Alice, Amy and Amelia if they are happy sharing with a transgirl, and their parents too, you've broken the guidance) or you are getting children into a situation where their boundaries are breached and where their parents haven't consented to what's happening.
Likewise with adults, you may think "all transwomen are open and honest about their trans status" but there is NO onus on them to be open, under GG guidance. So if you tell your fellow leader "Debbie is coming, you know her, she's trans" then you've breached guidelines. If you don't tell your fellow leader Debbie is sharing a room with you two, you've put your fellow leader in a very uncomfortable situation.
And if you think that "parents won't object" or "leaders should be happy to share with Debbie", is that your decision to make?
There are things that GG has done in the past that I thought "well, that's a bit contradictory, but I'm sure we can make it work in practice". So I totally get where you are coming from - for example, there was some odd guidance on children of leaders where it sounded like if you took a 14 year old child along to help with a group of Rainbows, but the child wasn't a YL, you had to have a separate adult to supervise the 14 year old (I can't remember exactly but it was along those lines). In practice everyone was saying "they've made a mistake, ignore it". But if you do something that's not in the guidelines (e.g. ask parents if they are happy with Alice, Amy and Amelia sharing with a transboy) and something happens, you are liable because you haven't followed GG guidelines.
This is what I said to GG - I cannot follow guidelines that conflict with safeguarding - and that's why they removed me.