Repair estimate questions: intake flap, airbag, motor mount, seat memory
 

I have questions about a repair estimate from an Audi dealer service department.

I have an intermittent airbag warning light, a check engine light, and non-functioning seat memory buttons.

$211 - Faulty seat memory switch replacement, faulty

Codes for the check engine light:
$480 - Faulty intake flap motor
$474 - Faulty left side motor mount (not cushioning)

Airbag warning light code:
$748 - Faulty rear left seatbelt, which requires replacing the entire back seat

My question is this:

Does the entire back seat have to be replaced as they say?
Are these common problems? I have seen intake flap problems and seat memory, but broken motor mounts? Rear seatbelt failures causing airbag faults? That seems unusual. Is it?

The total comes to $1913, which I need to pass on to the dealer who sold us the car under warranty. It just seems like a really steep estimate, and I wonder if they are inflated. This estimate includes 2 hours of diagnostic time at $119 per hour.

I've heard of a few people getting their motor mounts replaced. For the rear seatbelt, I imagine it's all tied in together in the airbag system, so it probably doesn't mean the airbag itself is defective, it's just listed in that section.

I had a bad motor mount (it was leaking hydraulic fluid), but it didn't throw a CEL. I think it was a little less than that (about $400), but in the right ballpark. It happens.

As to the rest, I have no idea. Seems a little extreme that 1) a faulty rear seatbelt would cause the airbag light and 2) the entire seat needs replaced. That doesn't sound right to me. Although, if it's under warranty, why care?