If your in-laws are adamant that the mashed potatoes be real (not instant), you can make them in advance and use your crock pot to re-heat them/keep them warm. You just lube up the sides of the crock w/butter, put the potatoes in and set it to low. Stir it every now and then to make sure they heat through, and check to see if you need to add a little milk. Maybe hubby could make them for you the day before, and then you just need to throw them in the crock pot an hour or so before you sit down to eat.
(You’d mentioned crock-pot recipes would be good.)
Regarding their demand for stove top stuffing, I have this to say:
Eeeeeeeewwwwwwwwwwwwwwww. Not to judge anyone or anything, but that really says a lot!

Of course, you could still stuff teh bird and save the good stuff for yourself!
I would keep the meal simple and satisfying, but honestly, with a baby that nurses every hour, they shouldn’t even be imposing on you. THat’s just not fair. On the bright side, maybe they like other processed foods, too, which would lessen your time in the kitchen.
OH! I almost forgot! MARKET DAY!!! They have a lot of great T-Day sides you can order and even (shhh, don’t let anyone hear this…)…nuke. They have really good sweet potatoes, corn souffle, etc. If your parish doesn’t do the Market Day thing, there are lots of other parishes in your area who do, I’m sure. Check out their website. They also ship direct, but the list of offerings for that option are limited.
www.marketday.com
One more thing. Lots of grocery stores, delis, and restaurants offer a full pre-cooked T-Day meal. They also sell sides (one year, many moons ago, we ordered our sides from Dean and Deluca, back when we worked in NYC. It was a splurge, but amazing!!!) That’s what we’re doing this year. I love to cook, but we’re going 2 hours away to my MIL’s, and she is not able to cook. Prices for a meal to serve 6-8 run between $49 and $75. The one we’re getting is $64.99, includes a 10-12lb bird, stuffing, potatoes, gravy, cranberry relish, green beans, apples and yams, dozen rolls, pie, etc.
Good luck!!!