will answer what i can right now. (on way out)
1: no idea never used it.
2: bsp switches
3: sv_pass blahblah
(has a lot of stored scripts)
also halo scripting bible http://hce.halomaps.org/index.cfm?pg=3&fid=2809
5: never really done it.
6: model what you want (maybe start from a plane, move verts, edges etc to create the shape you want then once your model is done and you think it is sealed (use convert to polygon mode, then select the border tool and select over your whole model, press F4 if there are open areas, then they will show as red lines surrounding the areas that need to be sealed) make a box, name it frame, link the mode/map to the frame.
make a box around your map flip it press M add a material in gmax/3ds. then call this material +sky click on the grey rectangle box beside diffuse. add a blueish colour to represent the sky.
7: check the ilist in tehlags channel http://www.youtube.com/watch?v=SgtC25pediM
9: model it from a plane etc. adding cylinders or what ever shapes you need. most of the time you will have to move edges, verts etc. practice.