Hey Summers ^^
To answer your question about that particular whim, he needs to create something excellent. I believe he can use the artist table under kids' activities, but make sure he's very inspired when he tries and even then, might not happen until later levels in creativity skill. The only issue I foresee is that maybe he has to wait till teen to get it, but I thought I remembered getting excellent quality drawings before, though I could be mistaken XD
As for the whiz kid question, yes, bonuses stack. So since he has the mentally gifted trait and giving him savant, the bonuses should stack. As well as if you bought morning/night Sim and the bonus for being in the proper mood, etc. Hope this was clear enough! I'm only now just getting some caffeine in me XD
