Are you talking about doing both on the same night? You actually could if you were to do the first CP show of the night, but I wouldn't recommend it, especially with a little one. If you're just talking about doing both on the same trip, then sure, I've done both on the same trip; when I go in December I want to do all the special Christmas activities. I don't do a park on the day I do the party, but instead I tour the deluxe resorts to check out their Christmas decorations, although I don't think I'd suggest that with the little one. I think your best bet would be to take it easy on your party day, and maybe do a character meal at Chef Mickey's before heading over to the party (which I like to do as well.) I would highly recommend doing the CP dining package to ensure getting a seat, and doing the first show, again for the little one's sake.