sometimes can you skip machining the head?

hi everyone. tomorrow when i get my hex socket for the vanos caps i will remove the vanos and pull the head. i have external torx sockets do i still need to buy the head bolt tool? i read in one post that i needed it, if i do then tomorrow is a no-go.
when the head comes off i have no clue what i will find. the engine never overheated while in my possession if that means anything.
worst case there could be cracks and stripped threads, ok, let's assume there are no cracks and the threads are all good and it's just a bad cylinder head gasket.
i definitely understand i need to clean the surfaces, without scratching stuff up.

then i will use a straight edge and check for warpage. let's say i find out that there is no or minimal warpage (I read 0.002" is still ok?).

basically if things go well, what are the chances of getting away without machining the head? and maybe i'll use a fine-grit sandpaper with a flat surface and just rub the head over it a bunch to make it all smooth again?

the block itself usually doesn't need to be machined or surfaced in some way because it's so big that it doesn't warp, is that true? (aside from thorough cleaning of course)

sorry for the stupid questions, i've never done a repair like this before.

sometimes can you skip machining the head?