Not the OP but I've worked very successfully pair-programming full-time on a fully remote team of 6 devs, 1 tester, 1 designer, and 1 product manager. All devs

Not the OP but I've worked very successfully pair-programming full-time on a fully remote team of 6 devs, 1 tester, 1 designer, and 1 product manager. All devs were quite senior except for one junior (and that junior leveled up faaaaaasssssst). We usually rotated daily so if a story took three days, the two people who started it weren't the same two who finished it. We all developed a similar coding style for the particular project, everyone knew every part of the codebase to some degree, and we felt a collective ownership over it--there was none of that "Oh, I don't want to change this because Sam wrote it and they'll be mad if I change it" nonsense. However, our timezones only spanned three hours.