Discovery Cove doesn't serve dinner. You can probably have a big lunch and a late snack in the afternoon and be done with the dinner.
You already have 2 days at Epic, so it's probably overkill, but you might look at going in the evening during one or more of your days in the other two parks. Lines are usually shorter at Epic in the evening, you can do a lot in the last two hours of operations. Have you ever been to Orlando before? The other two parks haven't changed a lot lately, you can probably do 1,5 days in each
It's a lot of dinners offsite. It's true, Disney restaurants are overpriced and sometimes not so great quality, but once you factor time lost and the extra expense of another rideshare, it's probably a wash. And you're missing on a lot of cool experiences. Red Lobster food might be better than Sci-Fi dining (but is it? I've been once and didn't fall in love), but the latter is way way cooler and something exists only in WDW. I'd dine offsite when you go to a waterpark in the morning and maybe when you go to Seaworld. In Seaworld food is not that great, but I ate at the shark restaurant and it was ok and for the view it was worth it.
Personally, I prefer to do sit down lunches instead of dinners. The reason is that the last hours of operations are always better than the middle of the day. It's shorter lines and dinner might prevent you from watching the night show, depending on schedule., Instead, getting off your feet in the middle of the day is very pleasant
I would go to Boma the day you go to AK, for sure. It's wiser to go when Christmas decorations are up, AKL is one of the best, but it's so much more convenient to go straight from the park.
If you have a fridge in your hotel room/villa, have groceries delivered or go do some shopping and have breakfast in your room. It's a huge money and time saver and would allow you to be more easily in the parks for rope drop.