For a 3 yo boy I'd keep CP and CM. Of course you know his interests the best, but it seems like these are most on target for his age. H&V also if he is into Little Einstein/Jo Jo. CRT is pricey and I haven't heard raves. Unless you think he'll love the castle an princesses, I'd save the money. I have heard great things about Park Faire, but unless he is into Mary Poppins you could probably drop that too.
I don't know how many days you are going so I don't know if you have too many booked. Personally, I find character meals a bit stressful (I have DDs 2 & 5). FIrst of all, buffets mean a lot of jumping up and down to coordinate everyone's plates. I also feel a little distracted, watching for the characters, getting autograph books ready, making sure the kids are not at the buffet when they come around. I think they are a lot of fun and worth doing some, but I can't handle too many. THis time we are doing CM for breakfast and PF for dinner over 8 days as our only character meals. But other people prefer buffets if they have picky (or diverse) eaters in their party or if their kids can't handle a long sit-down meal.