RE: frost seeding
Unc Al - Its all about seed/soil contact. If the sod (dead or not) prevents it, then No. The roundup creates conditions favorable to let clover dominate when planted after spraying, but you still need to make sure the clover hits the soil. A good set of diccs will expose enough soil after spraying. If you cannot disk - then any disturbment of the soil will help.
Frost seed ing works in this case because the thawing/freezing process gets the tiny clover seeds through the dead sod.
Good luck