“Almost all of the GOP debate schedule is already determined”.
No. Some debates have been scheduled. There’s no reason why others can’t be scheduled unless the candidates were stupid enough to agree to do no other debates.
Fox news could host some “discussions” — call them what you like.
FWIW.......
WASHINGTON – Today, at the Republican National Committee (RNC) Winter Meeting in
San Diego, California, the RNC announced that it has sanctioned nine debates
from August 2015 through March 1, 2016. RNC Chairman Reince Priebus presented a clear
vision for the debate process, including the dates, locations and sponsors.
https://www.gop.com/rnc-announces-debate-schedule-sanctions-9-debates/