If I know I am putting up a cloth walltreatment do I have to tape and mud the seams of the drywall? Does this include all drywall seams? also do I have to do the corners and at the ceiling?
Firewalls are only required between a garage and a living space and on the garage side only on residential construction (20 minute fire separation) and for fire egress hallways in commercial construction called "1 hour fire separation" walls.
As for the aesthetics of it, not taping the seams may show gaps through the fabric covering you apply and not look all that good when done. The taping does not need to be all that perfect, just flat and fairly smooth so it does not show through. A trick that wallpaper hangers use when applying thin foils and fabric is to apply "blank stock" wall paper first to provide a smooth surface that does not show any imperfections through the final finish covering. The wallboard should be taped for this too.