1)
http://www.grsites.com/textures/)
google: free textures
2) Only have to compile once on full vis. Can do fastvis if you just want to check for leaks (very handy)
Also, it should be sv_pure 0 this is no cheat mode.
The way I use is to type in the console (shift + ~)
devmap yourmapname
this to me is much easier and loads up you map. Just type your map name and no extension.
4) I'm pretty positive they can.
5) Make a new brush, select it then press n once or twice. A list will come up. For spawn points use info_player_deathmatch.
To add bot support download bspc.exe which is included in the Elite Force GDK. But for now bot support sux, they only jump around everywhere = no fun!
TIP: If you havn't already download the QeRadiant manual. It is a great reference. Try and get the pdf version.