I can't comment on Universal since I've never gone. I'd feel like a trader

I'll go some day. My sis has gone and really liked it, but felt my DD wouldn't like it. The rides are a little less tame for her. She was terrified on the Pirate ride (we didn't know it was dark and decended a few ft in the beginning). I'm not sure, but I don't remember hearing about their live shows like WDW (Hunchback). Check my website if you want to see some photos.
AS far as Downtown Disney, we usually go to shop. Ive been to Pleasure Island once when DD (dear daughter) was 5 and she thought it was too noisy. Some CM's got her ear plugs! Still didn't help. She loved the Comedy place though. Laughed and laughed and laughed along with everyone else. I'll never forget that! She had no clue what she was laughing at (over her head).
You should check out the Boardwalk for more free fun. They have dances along the boardwalk on the w/e. I don't know if your son would enjoy that, but the girls do. It's fun to just stroll along though. Resort hopping is another favorite. My DH (dear husband) loves to do that as well especially on the monorails. Listen to "please stand clear of the doors".... then the Spanish version. Our favorite part! If you're among the first in line, ask the CM's if you can ride up front. It's cool!
Ohana's is a restaurant in the Poly. It's really fun. It's a buffet with salmon, beef, turkey (THE BEST), and pork (I think). The kids can play games. They have a singer there (hopefully you won't get the annoying LOUD one.) I can't believe this, but I can't think of the good one's name. It's something like Kalua. Now, that will drive me crazy!
Check out this website as well:
http://www.wdwig.com/
It has menus and all kinds of things on it.
Chef Mickey's is fun as well. I'd advise getting PS for both Ohanas and Chef Mickeys.
Hope this helps! Kaleo, that's the singers name!