Since you asked, I'll give you my thoughts ....
I'm guessing that since you said 6 days that you'll have 5 nights of dining -
I'd pick either Boma or WCC just to see the lodges. I'd probably pick Boma for the food, with a buffet usually everyone can find something they like. If you'll be in the AK, make an early evening ressie for Boma, but give yourself time to look around the AK Lodge. But if you'll be in the MK area, and like hooting and hollering and (sometimes) silly antics, WCC is fun. Check over their menu to make sure its the kind of food you like to eat. Either of those resorts are worth a visit just to look around.
Coral Reef - How often do you get to eat in an aquarium?

It is pretty in there and if you don't like fish they have a decent steak on the menu. If you want to see Illuminations (and its not to be missed, IMO) I don't know if I'd chance a reservation after 7 p.m.
Spoodles - again, I'd check the menu to make sure its the kind of food you like (Mediterranean), but the Boardwalk area is kind of fun at night, all lit up, entertainment (we watched a juggler and magician) and you can get there by boat (or walking, but its more than a hop-skip-jump for sure) from either EPCOT or DHS.
Ohana - I've eaten there several times and enjoyed it, reviews here are mixed, a lot depends on server, time of day, phase of the moon ....

but it can be fun and the Polynesian is beautiful.
I've never eaten at SciFi, so can't discuss its merits over 50s Prime Time, but either would give you a "fun" choice at the Studios.
Whatever you choose, I hope all enjoy!
