Manifold Gasket and STud install Question

Had an Exhaust leak so i decided to change my gasket. Unfortunately the exhaust manifold is cracked but i got all the studs out with out breaking any myself.

I was curious what sealer i should use on the studs?

Also the front and rear top holes to mount exhaust manifold were broken off do they require the same stud or do i just use bolts?

Anyone got a lead on a cheap header or Headers?