It is not true that your daughter cannot control her rages. If it was, her rages would not be selective.* *
The truth is she feels uncontrollably outraged at people close to her slighting her, or perceived slights. She can't control these emotions, but she is 100% in control of her actions - her words were specifically intended to cause maximum hurt. She purposefully went back to the argument at later times.
When "slighted", she feels outraged and victimised, and wants to dominate and punish into getting what she feels is the just outcome. She feels entitled to behave like this. She feels entitled to physically express her anger at you, because she blames you for causing her feelings.
Read "Why does he do that?" by Lundy Bancroft about (primarily male) domestic violence - it's not because the perpetrators are victims or because they can't help it - it's because they're entitled and seek to exert control. Nevertheless, perpetrators usually claim that they can't control themselves, that they are victims and that they need help, and that their violence is caused by other people triggering them. It's not true. Do not let your daughter attempt this.
She will NEVER improve as long as she insists her behaviour is out of her control. She needs to accept that her feelings are her responsibility and hers alone.
The most urgent need right now is to salvage Christmas. Don't freeze, just postpone. This is what I'd do:
Your daughter should stay away for one more night to let things cool. Assure your husband that you agree there will be consequences, and you will postpone these discussions until the 27th, to concentrate on Christmas. Ask him to act normally until then. Tell your daughter there will be consequences, but that it will be postponed until after Christmas. Call a truce until then and see if you can get them to agree to not talk about it at all until the 27th.
If your daughter tries to initiate conversations prior to this, you and your husband should practice "grey rocking" - that is, reacting in the most neutral way possible so as not to give any emotional fuel to her (which is what she seeks). Give no opinions or information. Just say "ok, we will discuss this on the 27th".
Finally, your daughter is an now an adult. Your husband has absolutely no right to punish her or control how she lives. No matter how she behaves, she's not a child, and punishment is no longer appropriate. This is categorical, and your husband needs to accept the reality of having an adult child.
Instead of punishments and trying to break her will, there are consequences. As an adult, having her flights paid for her is a privilege. Having her rent contributed to is a privilege. She has no idea what a massive privilege these things are, most parents could not afford this at all.
You know in your heart she can control herself, because you've pretty much dismissed the risk that these rages would get her into trouble in Mexico. However, you should still put it to her that if she cannot control her behaviour, she will be in danger in Mexico - it will make her think.
I fully agree with your husband that the consequence for her abhorrent behaviour is that you should not pay for her flights. Your daughter needs to learn that actions have consequences, and that apologies and excuses aren't a means to escape this.
I do not agree with him that he should otherwise prevent her from going to Mexico. He has no right to interfere with her life as an adult.
Going forward, you should agree ground rules for the future. For example, if your daughter is angry and shouting, she should contain this in her room. Disrupting work is unacceptable.
Allow her room to be a safe space she can retreat to for when she does feel violently aggrieved. Other family members should not approach her in her room when she's angry and needs to cool down.
Your daughter should be made aware of consequences of further tantrums. One should be withdrawal of the privilege of subsidising her living costs.
You need to talk to both your husband and daughter and figure out some ground rules for interacting, and ways to avoid aggravating each other.
It does sound likely that your daughter has a personality disorder, most likely EUPD. She does not have autism because she doesn't have impaired executive functioning, aside from emotional regulation, which can be better explained by EUPD. She also doesn't have rejection sensitive dysphoria, because their whole lives revolve around avoiding feeling rejected or criticised, and have obviously low self esteem. Your daughter sounds otherwise quite functional.
Any diagnosis is only relevant in that if she is found to have EUPD, she may benefit from mood stabilizers and/or therapy. Regardless of if she has any condition, yes, she absolutely should still face consequences, because her behaviour and emotions are still 100% her responsibility.
This needs to be nipped in the bud for her own sake. One day, she will lash out at the wrong person, and they may not stop at a slap. Also, if she's ever genuinely wronged, her history of poor behaviour will mean that people won't believe her.