The head coach can designate any staff member to step in temporarily for a full time coach if that full time coach is unavailable for various reasons. Or in an interim role if there is a job opening.

You merely need to designate that individual and inform the NCAA as to the dates where the interim person will be filling that spot so to speak.

Tech did have their max allotment of 4 coaches out during July. That does not necessarily mean those will be the same 4 coaches we see in those exact roles in September.