Hi subedei. Pete would be better placed to give you those answers as I’ve been working low poly for too long but I will give it a go.
Very Good Max Video tutorial: link
Watch Part 09 – Unwrapping UVs for Organic Models movie two.
Breaking Pieces off – I would try and avoid it as you may create seams. Maybe just the ears if you are concerned about them.
Mapping- Not used pelt mapping in max to un-wrap uvs myself but hear it is a good tool. Would be useful for the ears if your separating them. Give it a try and just texture with a checker map to see any problems.
How do you flip the UVs – I’m a blender man so I may be thinking about this wrong but if as pete suggested your head is symmetrical, can you not just cut the head down the middle discard half, texture it, duplicate the mesh and mirror it or use symmetry modifier, your Uv’s should mirror too. So seam the two meshes and then your Uv map is all setup if you want to add asymmetrical detail to the texture? Any way glanced at tutorial above and it covers this correctly.
Select verts Max edit UVW’s has a vertex button – then you just marquee what you want as far as I know.
Straight even lines – Can’t really be done for organic shapes to my mind. Just distort your texture accordingly.
Cylindrical mapping – Yep distortion at top and bottom of head will happen with this method – just the way the projection works. Someone needs to come up with pill shaped mapping!
Speed up unwapping – Are you unwrapping half?