Pooh will be at Tony's Town Square while Crystal Palace is closed.
My son went to Disney for the first time at 19 months. Here is what he liked the most: Small World, Dumbo (Alladin and Tricertops spin at AK are similar thrills with shorter lines which have since opened), TTA, Tommorland Speedway, Winnie hte Pooh's Honey pots, Peter Pan, The Train, Country Bear Jamboree, Parades, Beauty and the Beast Show, Bear in the Big Blue House show (AKA Playhouse Disney), Kilanmanjaro Safaris, Live shows in Epcot's Wolrd Showcase, The Boat Ride in Mexico, Spaceship Earth, Journey into your Imagination, Food Rocks and The Land Boat Ride.
Some of the above rides are dark, but otherwise Okay. Anything with a drop (even a little one like in Norway) would make him scared and clingy for the next several rides.
Take advantage of the Baby Care Centers. They are ni, quiet, air conditioned places for your little guy to unwind soem even have toddler toys and movies. The yare highly underutilized.
Like so many others have said, take your time and go at your little guy's pace. If he wants to ride Small World over and over again, let him. It's fun just to watch their faces light up at this age.
Also, to get my kids used to the larger th life characters before our first visit we went to every "character" thing I could think of for a few months before our first trip. When Clifford was at Banes and Noble we went, we saw the Easter bunny several time etc. Many visitwere just looking from afar and talking aboutHay htere's hte Easter Bunny", etc. By hte time we got to Disney my little man was no longer timid aorund characters at all.