Hopefully Elston is retained in some capacity so he can continue to be recruiting coordinator. As far as Lyght, Gilmore and Hudson...it depends on how they fit with the next DC. The new hire needs to make that decision.
Offense just needs changing of responsibilities. Sanford needs to be handed keys and made a real offensive coordinator. Denbrock can maybe do WRs and TEs since he won't be involved in playcalling? Denson and Hiestand need to be retained.
Also changes are needed in the S&T program, but I don't know enough about what is exactly wrong to guess who or what the problem is. Is it Longo? Quinn?