First off, it’s no wonder you didn’t find any information if you were using the forum search engine. IMHO, the forum search engine is totally useless and extremely frustrating. Your best bet for finding information is the ZBrush Wiki or Google. The searches works much better there.
Splitting up your mesh… Go to your lowest subdivision level and, using Selection Brush (Ctrl+Shift), split up your mesh into seperate polygroups (Tool > Polygroups > Group Visible) then split the polygroups into seperate subtools (Tool > SubTool > Groups Split). While still on your lowest subdivision level, select each subtool and crease the edges (Tool > Geometry > Crease) to avoid seperation when you step back up in subdivision levels. Keep in mind that you can’t sculpt across multiple subtools so avoid sculpting near the seam area. Only way is to merge the two subtools and then split them back up later. Also, if you merge subtools, they have to have the same number of subdivision levels.
What types of maps to use…I don’t understand what you mean as this has nothing to do with splitting up your mesh. However, each subtool can have it’s own texture providing it has UV’s.
How to deal with seams?..one way is to hide them with another subtool ie: belt, clothing, collar, hair.