I think you should be able to eat at most of those places, especially if you're flexible about the time of your meal. I'm going at the end of August and just started making ADRs a couple weeks ago. The only places I couldn't book were the really popular restaurants like Ohana and Chef Mickey's.
Of the places on your list I've been to:
Crystal Palace - I've been for both breakfast and dinner, and feel that this is definitely one of the better character buffets. The characters circulate pretty efficiently (you'll get great picks without having to wait forever) and I think the food is pretty good. Going again for lunch this trip
Coral Reef - I've read some pretty mixed reviews about this place, but my experience was great. We ate around 2, so we didn't have to wait to be seated and the food came out pretty quickly (many complaints I see have to do with slow service, so I think making an ADR at a non-peak time will make for a more enjoyable experience). The server was friendly, the food was good, and of course it was nice to watch the fish! It was definitely enjoyable and I would go back again.
Mama Melrose - Eh. I really want to like this place, lol. I've been twice, and both times I felt the food was pretty mediocre. Not terrible by any means, but just not really worth the money or the time. The service has always been very good and some things on their menu are definitely better than others. Perhaps I'm just ordering the wrong things. I probably wouldn't be back, unless I was able to make an ADR for the Fantasmic dinner package.
I haven't been to the Wave, but I'd really like to try it, as I've read some good reviews.