the only thing about rushing back to the safari for a fast pass is that you miss so much of what makes the AK magical--
right when you go into the park there will be CMs holding out various animals to look at, and there are tiny little meandering paths with briliant flamingos and fish and little caves to explore. While it's uncrowded, this is the best part of the day in the best part of the park.
Having been there a number of times, and never taking the time to stop and smell the fishies, I would explore the front area and wander the little paths. If you have another adult, maybe send them WAY to the back for the safari FP, then have them meet you by the Tree of LIfe; you'll get that far by the time they make it to the safari and back.
One warning--the safari ride is very jerky. Depending upon how robust your little one is, you might need to do baby swap.
There are 2 jungle trails no one has mentioned. One has birds and primates and the other has bats and tigers (among other things.). These are much better in the morning, and worth lingering through.
The bird show is our favorite part of the park.
When my DD was 2.5 she LOVED the boneyard. Again, you'd need one adult to sit with the little one, and one to escort her through it. Be sure to "talk" about what to do if someone gets lost.
If they want to see characters, you might see if there is a PS available at restaurantasaurus right at the close of breakfast (around 10:30). Otherwise, if you decide to skip nap, make a late lunch PS at the rainforest cafe. You exit the park, get a stamp and go back in.