Well obviously if the dormant spots are bermuda the rest of the grass is a cool season and it looks like fescue to me but hard to tell from the pictures. But I am going to go with tall fescue pretty sure.
That said, I have never switched from a cool season to a warm season like bermuda especially on a lot that size. Usually warm season grass will take over a cool season, but I would kill off all that existing (except the bermuda) and then replant if it is a lot of weeds and crabgrass like you said.
And I would still get some top soil right before you seed even if it is a light coat on top, it will ensure the seed gets good contact. Having all those uneven spots filled in is crucial as well, you need it nice and level if you don't want problems later on with weeds and water retention/drainage.