I was a planned HB turned hospital transfer w/my twins. We had a very supportive OB w/lots of twin experience at a fairly laid back hospital. I was full term.
Here are some answers to your questions:
I don't remember masks... no, no masks. The MW and my DH had to put on those cheap scrubs, but I wasn't focused on the fact that they looked like smurfs.
Moving from the hospital bed to the operating table was stupid. I remember thinking, 'You've got to be f*cking kidding me.' So, yeah, if you can avoid shuffling on your back from a bed to a cold, hard table while contracting and pushing, I highly recommend it.
I remember thinking that there were not that many people in the OR. I suppose it was b/c I was full term and the OB was rather relaxed.
I had feared and dreaded an OR birth, but it really was not bad. As w/Louis Lane, I was too 'in the zone' and was able to labor mostly at home and then in an L&D room until it was time to push. The worst part of it, to me, was the fact that the hospital staff whisked the babies away to the other side of the room as soon as they were born, to weigh, measure, & suction. I didn't see the babies until after they were already wrapped up in blankets. Bleh. I don't like to look at the OR photos b/c there is one of twin B laying in a pool of blood between my legs, on the metal table, immediately after the breech extraction. She should have been handed to me. So if I had to do it again*, I would make sure that the babies were handed to DH or I immediately after birth and insist that the weighing and measuring wait for at least 20 minutes or until we were ready for it. I would have more talks w/my OB in case of hospital transfer to assure that a hospital birth would be as "nice" as possible.
*If I had to birth twins again and they were di/di, I would find a competent provider & plan a HB or travel to the farm. If they were mono/di, as mine were, I'm not sure if I'd plan another HB.