Ok,...
Belts will fix any speed or wow issues and any "heads stuck in up position" problem. Pinch roller replacement will fix any remaining speed or flutter issues and some more serious tape-eating issues, and like any other rubber part it will deteriorate over time and need replacement at some point. Personally, I'd be dubious of any motor replacement, but from the description you gave "idler replacement" or "idler tires" replacement would be recommended, (responsible for FF/RW and takeup functions), again (idler tire replacement) is low cost item with a fair amount of labor involved. Button panel is a specialized TEAC part that you may find on other sources (eBay), but is probably less hassle to have TEAC do this one, like one stop shopping. VU meter bulb replacement is labor intensive, but little in parts and not too complicated.
All in all, that sounds fair. Labor costs way more than parts and this unit needs a lot of TLC. However, I'd be interested if the record/repro alignment is included in this cost also. I'd kind of assume it is, but you know what happens when we assume,...
If your playback drops off more than about 1/2dB lower than your recording levels, then I think it would benefit from the calibration of the electronics, and I think that's important to include when you have the thing open.
Think of it this way, it can take many hours to do even the seemingly simplest of repairs. If you've seen inside these things, they were a wonder of technology and are quite complicated. The record/repro alignment can take several or many hours of tinkering, depending on how particular you are about getting it spot on perfect, less for "just good enough". More hours for a novice or weekend warrior, probably less for a fully professional tech. Original price was $1200 for the 244, and one in proper working order is still a worthy Portastudio that still holds it's own vs. many other similar or competing devices.
I've refurbished a 244 myself, replacing the rubber parts (1-2 hours) and spending many hours (appx. 8-10 hours) tweaking the record/repro electronics. Of course I was shooting for spot on perfection where that was concerned, but it is a tedious, royal PITA when you get down to it. I turned around and sold this unit for $225, and it was probably worth more, based on my original cost (used), the number of hours I spent, and I guarantee I was selling the unit in much better condition than when I purchased it from the previous owner.
I guess what I'm trying to say is don't sweat the cost. Most people like you and me have bought seemingly good deals then ate our lunch on TEAC repairs, but in the end it's worth it. TEAC will do the repair efficiently and right the first time, and not jack you around endlessly and jack up your unit worst than before, as so many off the street techs might do.
If you don't like it, you can sell it for $450 as "newly refurbished" and I think you'll recoup your costs, if it comes to that. Not sure if this post is any consolation to you, but I think you're doing the right thing if you value the 244 for the great unit it is, and as always YMMV!