Do they have handicapped riding carts to rent and how much are they?

ECV rentals are available inside the parks $50 per day plus a refundable deposit. Search the website for EVC Rentals for mor info and numbers to call

Yes

Yes they do, I believe is like $70 and you get $25 back.

Yes they also provide express service so you dont have to wait in line.

They do. Don't know costs but if you call guest relations they are super friendly and nice