For thanksgiving dinner go to openpages.com to see which restaurants are serving that day. Usually set times - but you can get an idea of types of food and price ranges.

For NYC with a 7 year old - must dos

Museum of Natural History - great dinos plus IMAX movies
Planetarium if he's a space kid
Central park for exploring and playgrounds (look at web site of the Central park Conservancy)- don;t miss the small zoo
Staten Island ferry ride across the harbor (free, runs 24/7, views of the Manhattan skyline on the way back are great -also a more distant view of the SoL)
Top of the Rock
Tour the Intrepid and don't miss the Space Shuttle
The Met (I know most people think it's an art museum, but little kids live the Egyptian section/mummies, the Temple of Dendur and the arms & armor)
If he's not used to public transit just a ride on the subway might be fun (but not in rush hour)
Take in at least one b;way show - perhaps Lion King for him (but get tickets NOW)
Consider the Circle line 2 hour trip around Manhattan - or one of the ferries to and fro NJ (they're for commuters, but the views are still great)
See parade balloons blown up - park next to Mus Nat Hist the afternoon and evening before (but realize there will be many tens of thousands of people)

He might like eating at Ellen's Stardust. Basic diner fare but the waitstaff are "resting" B'way chorus boys and girls

A lot of restaurants serve Thanksgiving dinner in NYC. I have been to Bar Americain and Artisanal several times over the years and like both. Last year I ate at Maialino and had a very untraditional meal of roast pig, but it was delicious (they also had turkey). These options are all going to be at least $50, but there are cheaper options. Almost every little restaurant in NYC has one starting at $20 and up. I'm sure the Loewes Regency itself will serve something, but it will probably be hideously expensive.

I don't know the restaurants on the Upper East Side that well, so I'm less able to make recommendations close to your hotel. But I can say that it's pretty easy to get around town once the madness of the parade is over, and if you can wait until around 3pm you'll find the city fairly quiet except for Midtown where they will still be cleaning up. You could head down to Chelsea (perhaps Colicchio and Sons, which has done a Thanksgiving dinner in the past).

For most of these restaurants, making a reservation 2 or 3 weeks in advance is sufficient ... but a full 28 days out for Maialino is better. It's pretty popular, though they were still accepting walk-ins when we went last year (we had a reservation).

Friend of a Farmer is often recommended for T'giving. They book up quickly. Near your hotel Park Avenue Fall has very good food, more upscale.

The Radio City Xmas Spectacular is a must. There are discounts floating around online but may not be good for turkey day. Here's one that would work for the day before. http://www.radiocitychristmas.com/new-york-promo-pages/EM35.html

Skating in Central Park is fun. Look on gold star.com for discounts that might promp some ideas.

NY Traveler has your list on the money and probably in that order. I would especially vouch that the Egyptian area at the Met is fantastic for kids.

I am not sure a 7-year-old boy would like the Rockettes that much. I have done their road show with my daughter, and I remember thinking my boys would have been bored.

Here's a simple way to zero in on whether a seven-year-old -- or even a 107-year-old -- would enjoy the Rockettes: buy a video of one of their performances (a used dvd is available for $5 including shipping). If the person watches the video and say, "This is boring," then s/he would probably find the live show boring as well. If the person says, "I can't believe anyone can actually kick THAT high!", then s/he would probably enjoy seeing the show live.

I know -- a video doesn't capture the magic of a live show. But checking out a video might either rule out the idea or make that person look forward to the show with great eagerness.