Barring some unknown episodes from the first ten seasons, Pat or whomever is the first African-American model on the show. This may or may not have been confirmed by those that have the information, but it's possible that one of the 3 regulars were absent within some of those unknown episodes from 1972-1982, and then an African-American or any other minority model filled in. Not likely though
I'm not sure about how they would've handled a situation if Holly had left permanently in 1984. I don't know off the top of my head how busy Kyle was around that time, but I think it would have been her spot to accept or reject if Holly hadn't returned.
Looks it December 5th was the earliest date, and that would be consecutively. It's tricky (at least for me); there was a week that was out of order, that aired in November, and that excluded Holly