I need help approaching the drama with my rehearsal dinner for our wedding!!!

Kate

So my in-laws are paying for our rehearsal dinner, our dj, and photographer for our wedding. I am so thankful for their help and putting towards our wedding. My parents are paying for the rest. Anyways, I have really bad social anxiety when the attention is on me, I am an introvert and my anxiety symptoms include me feeling like my throat is closing/nausea. It sucks, but I’m working through it. I hate eating in public because there’s lots of people around and I feel nauseas due to my anxiety. My fiancé and I agreed to do a cocktail hour type rehearsal dinner instead of a sit down type dinner so I would feel comfortable and avoid an anxiety attack the night before our wedding. His father proceeds to call him and say he’d rather do a sit down meal, etc etc. I have already explained to them my anxiety issues, and they agree to my face But then call my fiancé and say otherwise. Is it selfish or rude to say no even though they are paying? My father offered to pay for the rehearsal as well. Should I let them know that we want an appetizer/cocktail type rehearsal dinner, and if they don’t feel comfortable paying for that my dad will? Or what should I do? I am out of options. My only other option is to do the sit down dinner, and excuse myself when it’s time to eat or something. Someone please help!