eliza did a great job answering your questions, and I'll toss in a few comments.
If you are talking about this coming December, you are probably already too late.

VWL books up very quickly for December vacations at the 11 month window in January. It is a very small DVC resort, so it is a challenge to book there if someone isn't an owner there. So it could very well be a moot point. Sorry to be the bearer of disappointing news.
The studio will give you more space especially if you don't unfold the sleeper sofa during the day. It will accommodate bed rails if you choose to go that way or you can use the pack n play. In addition to the fridge, toaster and microwave it is just easier to be in the room with the sofa. In a regular resort room your only option is to sit on the beds to watch television, for instance.
Your DH sounds like a wise man.
The theming and details that make WL so great have been carried over to VWL, and in no way do you feel like you are "leaving" the wonderful feeling that WL conveys. What you might feel like after enjoying a meal or time at the main pool is "Now we get to head over to our great accommodations".
Trash & Towels works well for us, but I have to admit we don't use the studios. There is a laundry room on the first floor of the villas that is free of charge to VWL guests. It is not shared with WL guests but I can't swear that they won't try to come over and use the free laundry. (grrrrrr)
I think that's a great idea. Tell him to avoid the DVC desk in the lobby though or he might come home with more than impressions of a great resort!