IMHO, they're using both barrels as there's no way that all those parts are bad, probably a junior, inexperienced tech is telling their service writer that.
Now........it's possible that if there's a 448 code (with 442 or 446) that the air pump is siezed and if so, it'll need a new air pump and check valve BUT when an air pump fails, it's not unusual to get an O2 sensor code at the same time. I've not yet seen where both O2 sensors fail at the same time (especially with an air pump) and if there are 435 and 436 codes together at the same time, it's usually caused by vacuum hose leak, not 2 bad O2s.

If you have 442 and 446 codes for the air pump yet the pump still works in test mode and isn't noisy, then you can get by with just a check valve only.

So.....I'd ask for more specifics but there's no way I'd have all those parts replaced at once. I can see the air pump and check valve (if the air pumps siezed and/or noisy) but I would then just ask to have the codes cleared (which has to be done anyway) and skip the O2 sensors at this time. Wait and see if the O2 sensor codes re-appear but do make certain that all vacuum hoses (lines) are OK too.