Normally AC unit does not have a sealant around it. They use a foam gasket under the unit
As for other items on roof you can remove the self levelling lumpy stuff but myself I just went right over it with Eternabond tape that was wide enough to cover both sides easily.
Livin the dream... Retired!
TV 2016 F250 Crew Sterling Gray SB 6.7 PS airlift ultimate Air bags
2017 Eagle 321RSTS