Does the wheelchair rental site in the various parks open at early entry?
I believe so- you can ask over on Touring Plan’s WDW Lines Chat where folks are there now and can check, or email or call-
Disability Services at (407) 560-2547 or email disability.services@disneyparks.com.
Lines chat where users are there now and can check-
https://m.touringplans.com/wdw#_chat_page_1