We are planning work for several expensive jobs for our 75+ year old house (1 story plus small loft-total 2000sq ft- pier and beam foundation) in a mild/Southern climate - i.e.Gulf Coast

We will be hiring contractors for jobs below - probably 3 separate jobs but just starting to plan, everything is on the table right now.
Without any input from anyone who knows this kind of stuff (not me), I have put list below in order of how best at this point I think to do jobs. Does anyone disagree? Does order/sequence matter? Best to keep separate? Should I put this question in the roofing forum or A.C. forum?

first) New Roof (summer time when its hot is best, right?) - removal of previous layers needed - some plywood replacement needed

second) New 4 ton AC unit to replace prev unit (part in attic and rest outside) - wider attic steps recently installed

last) New attic insulation (probably replace totally inadequate old floor bats - new insulation probably to be blown in but maybe combination with batting between loft wall and attic, opinions?)