Hi, Elizabeth! I think you'll be surprised by the rockstar treatment your 7 year old son gets at princess character meals. Plus, he'll get to eat, and what 7 year old boy doesn't like that?
We love taking our sons to character meals with the princesses. Like your daughter presumably will be, there are many girls decked out in their princess gear. There aren't as many boys. But this works to your advantage. The Disney princesses recognize this and treat the boys like princes. It makes my oldest son blush but he loves it (and he giggles uncontrollably at their attention.) I remember being 8 and blushing at my first experiences with the princesses too.
I don't think there's anyone who would not be in awe of eating in Cinderella's Castle, which is why Cinderella's Royal Table would be one of my recommendations. The decorations and pageantry aren't overly girly and there are plenty of atmospherics that butch it up enough for even the toughest of boys. He'll even get a sword there. Akershus at Epcot is also a good time.
Cinderella's Happily Ever After Dinner at 1900 Park Fare at the Grand Floridian is more girly than the other two mentioned. You could always do a special dinner with your daughter here while your husband and son take a mini-mancation and do something more "guy like," such a Pirate Adventure, the Pirates League or tackling the three mountains of the Magic Kingdom nearby.