Passenger CV joint and one sided rear brake - 2013 Plug-in, 230,000 miles

IMHO: I would take it to a tire & brake repair shop. There's nothing special about the suspension & brakes on this car that requires dealer intervention. I would do the work myself. 1.0 to 1.5 hrs per half-shaft (~$75 each rebuilt or $300 each new OEM) and 2 - 3 hours on the rear brakes; depending on the amount of rust on those calibers.
The reason the shop is incentivizing you to replace both half-shafts and not offering a boot replacement is based on the mileage of your car. If I owned the shop, we would both be peeved if the other side failed a few weeks or months after replacement. Bad feelings all the way around, from a warranty work perspective. That's why most respectable shops won't do "patch-work" - it's all or nothing.
The rear brakes calibers needs to be rebuilt or replaced, because the slide pins the calibers float on - seems to be frozen in place. Just regular braking should've scrubbed the rust off those rotors, just like your front. You shouldn't have to resort to B-mode to clear rust off the rotors, unless something isn't working correctly. New calipers ~$90 or rebuilt ~$60 each - pad and rotor kit ~$70 pair.

Hope this helps....

PS: make sure the shop disconnects the battery, BEFORE cracking open the brake lines. If they don't know this - DO NOT get the work done there. Flush-out the entire brake system with new brake fluid while your there.

 

Take your chances either way with the CV replacement. A shop is going to do what a shop does and there's no way you're gonna know exactly what that is, even if you know the mechanic or owner of the shop.
B doesn't do anything to the brake pads and or rotors. Don't know what thread you read that in, but if it was here, it was bad advice.

There are plenty of tricks when messin with brake pads and rotors, How well any of them work is up for lengthy debate. There is a difference though between a decent brake job and a slapped together install of pads and rotors.