and 45 T&F roster spots, do the distance runners on the XC roster also take up a T&F roster spot if they are competing in track? So, are there really only 28 T&F roster spots beyond the distance runners? If that is the case then there wouldn't be enough roster spots to carry all the athletes necessary to compete in all of the events plus relays.

There are currently 61 women and 60 men on the Track and Field rosters at BYU(including distance runners).

The roster limits are pretty straightforward for most sports but for Track and Field and Cross Country you have two things being treated as separate sports but for a certain segment of athletes they are the same sport.