traveling with little kids

Hi! I'm staying at the Poly with my 18 mo old and 5 yr old Oct 4-8. Hubby just got a new job and already has a negative vacation balance from a trip we just made to Puerto Rico, so he will be teleworking. Which is fine because he doesn't have my boundless level of Disney energy. Any advice on...

My mother, my three kids (10,6, and 7m) and I will be flying in on Sunday April 25th. I was originally, before I read much about it, planning on using DME. My son would flip of he got on yet another disney bus (he's autistic and disney busses are his jam lol). Also, having 2 that need car seats...