Stopping progestin while on Zonisamide

Hello, i write on behalf of my 48 year old nonverbal autistic/epileptic daughter.. been having issues with Zonisamide, 30# weight gain in 16 months, some kidney values slightly up, ammonia was up but treated, been on birth control to stop periods for 20 years, 5 years ago taken off estrogen for blood pressure but on mini pill
Now thinking change to Lamictal but dr wants to abruptly stop progestin thinking it causes weight gain, never had weight issues till Zonisamide
Also on Seroquel for many years , behaviors,and recently has lip smacking etc
Can't change that too ?
I think low dose progestin okay so her hormones don't get affected while changing AED?
I am conservator/ mom over 75 trying to make good decisions..
Any opinions welcome! Thanks