First let's address the service:
You are entitled to 1st rate repair regardless of cost because the other drivers insurance company is paying for it, not you. For each error/flaw you find, I suggest photos for proof.
Lastly, I hope you are speaking with the Business manager and not the shop foreman. Your shop foreman is trying to compensate for his workers lack of skill; the Business Manager/Owner will be concerned with his business rep and referral base.
Recommendation: take photos, discuss all future transactions with the Business Manager/Owner, have him annotate all flaws and future work on new estimate sheets or continued on subsequent pages of the original work sheet.
Quality of Work:
Unless you were involved in the selection of the Body Shop, not much you can do really. Be patient and work with them while they repair your car to factory specs as you requested. I would suggest a 3-strikes and your out rule. If you hit that 3rd strike, I recommend discussing the businesses problems with the local
BBB. Before hand, make sure they are a member!! Don't know how it works over there, but that will have an impact on the service you receive from the BBB.
Lastly - style of work and methods:
Dependent on where the damage is should dictate the requirement to remove the bumper or NOT. If they didn't have to do any "body work repair" - just paint, I would have never removed the bumper. And like you mentioned, why they didn't tape off the remainder of the car for the job is beyond me. Now, for obvious reasons, they may have felt safer removing the bumper to do the job without the car itself in the paint-booth, but its a workmans call.
Overall, the small polishing tool they are referring to isn't that hard to come by, especially in a HUGE city like Philly. They should of had that car done in 6 hours or less total time! They charged over $800 to R/R the bumper, repair, prime, paint and refinish the piece, and it took 2 days. - they had the wrong guy on the job. Period!
As far as repainting the whole thing, that is a confusion of terms. They only painted the area concerned where they used primer. (I just hope they used Euro-prime for flex in the bumper.) The clear-coat will provide plenty of protection for the paint regardless of depth/number of coats. As far as orange-peal and texture go, that is decided by the painter - if he knew what he was doing he could have shot that whole bumper in clear and matched it perfectly the first time. I only have 6 years experience and know that GM uses HVLP, fast-cure-sprays. (Increase your activator in your clear and bump up your gun about 10psi and u get pretty damn close to a factory job.) Geesh!
For your knowledge when you return, your answer is yes, they can sand the new clear-coats on the bumper with some 1500-2000 grit paper and reshoot with 2 more coats. "IF" they have to re-sand again to finish the job, they need to invest in a new painter or some new guns.
They would have to sand for a very very long time, to sand thru the clear coat and hit paint. If they hit paint while sanding it will be very dull, like a matte-coat appearance. You will notice it immediately!! When you spray on "Paint" it dries dull, not shiny. The "Clear-Coat" is what makes it shiny, not the "paint."
Good Luck man!