You should be able to purchase nice raised panel 4 panel interior doors in that price range. There's no benefit provided against warping by going thicker. I just dealt with a 12" beam that had warped over the years (It and all of the posts and beams in our house were installed after only a year of drying outside). I think that it would actually be pretty unusual for a raised panel door built from kiln-dried lumber to warp if it's finished. Sawdust and wood chips molded into things arguably have a place in home construction, but for finished surfaces, it's hard to go wrong with the real deal.

First time I painted our whole house (years ago) I painted trim and door molding cream and doors themselves a very light shade of tan (very light but there was a bit of contrast). Didn't look bad. This time around I went all white because I really wanted more color on the walls. I think what you describe sounds nice. As Michael says, it's what you like ;) If you check over in home dec (try searching 'painted ceilings' or just 'ceilings'), there was a post in the last month or so about painting ceilings. There are some photos of high ceilings like yours done same as wall and a shade lighter, both are very pretty. Oh, don't want to send you on a wild goose chase, hang on, I'll go look for it......Ok, here you go. Scroll down this post and look at lindybart's photos.

If you can fit a 2x4 in the shim space, thats a pretty big gap I agree. Usually a rough opening is 2" larger than the door size and the jambs take up 1-1/2" of that space leaving 1/2" left. That would allow for 1/4" shim space on each side. If you want to sound proof the shim space, you would be better off with wool or denim insulation than spray foam. Sound is stopped by dense items, spray foam is not very dense. That being said, as recommended you should change the doors to solid core instead of hollow core as well If for some reason you feel you must spray foam (even though you shouldnt because it will be a pain for anyone adjusting the door in the future), use latex non expanding foam (DAP Dapdex) otherwise you will ruin your door (aka it wont close or open properly). The latex foam is also easier to remove in the future if needed.

I know what you saying ladies, it's always good to have an extra opening. I guess the way they looking at it if you awake, you can hear the smoke alarm and have enough time to escape simply put... If you sleeping you might not hear the alarm, and by the time you hear it and wake up, it could be too late, so each sleeping room must have an additional escape route or rescue entry point so the fireman can climb in and out wearing full gear. I can see in NY this being enforced more because most houses are attached and even single family homes are semi-attached or separated by the driveway... not to mention they make any hole in the wall habitable because they rent them for 1k a month... You see basements with a stove next to a bed and table and a clothes hanger and they get 1000- 1500 a month.