Posts 18 - 21 of this thread have information about the steps into rides and difficulty.
disABILITIES FAQs thread - stuck near top of disABILITIES Board
Just quick answer for your specific ones
Pirates - difficult. The seat is low; easiest way to get in is to have someone from your group already in and someone outside to give a steadying hand. Step onto the seat, then down to the floor. Do the opposite to get out. Gravity helps when getting in, but works against you going out.
Frozen - difficult. The boat has a high side (6-8 inch) you need to get over and then step down to the seat which is down below the side. If she has any issues with bumpiness, the track for Frozen is pretty uneven and bumpy.
Living in the land - pretty easy. There is about a 6 inch up over the side into the boat. If she doesn’t feel she can make it, the attraction has a wheelchair accessible boat and she can borrow an attraction wheelchair to use it.
Grand Fiesta - a step down over the side of the boat, then a step onto the seat and down to the floor. For most people, it’s not as difficult as it sounds. The seats are close together, which makes getting in harder. Many people find this works best with one of your group inside the boat and one outside to help get into the boat.
There is a wheelchair accessible boat and she could borrow an attraction wheelchair. The wheelchair boat has a flat entry and a ramp; some guests ask for the wheelchair boat and walk in, but there are no handrails along the ramp, so it may not be easier.
Small World boat is very similar, so whatever works on one, will work on the other.
I am also reading mixed info on Peter Pan belt slowing down.
The OFFICIAL answer for Peter Pan is that it is ONLY to be stopped in rare, special circumstances - for example, child on Wish trip.
I have gotten the consistent same answer on Peter Pan from Disability Services management and Fantasyland Lead (not just contacting a random CM by email or phone). The main reason is that stopping it keeps guests suspended high above the ground during the stop. There is little to keep the guests from trying to climb out.
Some people have reported it was stopped for them, which is probably an individual CM giving pixie dust without knowing they are not supposed to stop it.