I'd agree to use up wife's miles first, keeping a larger balance together in your account. Better than spending yours first, ending up with two accounts just shy of the next award ticket you want.

Unless the fares are outrageous, I'd be inclined to just buy the ticket rather than use 25k miles for a one-way AAnytime award in coach. You won't be upgrading that flight with stickers (the computer knows the difference between Y paid fares and AAnytime award tickets booked in Y) and you'll be spending a lot of miles for a domestic ticket.

If you just buy the tickets, you'll earn more miles and you can attempt to upgrade (with stickers or miles). I'm not a fan of sAAver coach awards and I'm really not excited about wasting double miles to sit in domestic coach. Miles can be redeemed for international biz and First class tickets that make for very special trips. Domestic coach? To each their own.