Any question answered...

I'm sure that there was a thread which dealt with these kind of questions but I can't remember/find it so asking here. Sorry for the long post!

I'm looking at a 1991 Dawes mtb in Reynolds 500 and wanted to know if there is going to be any funny sizing to thwart a build. I've got a 9 speed Deore gear set I want to use.

1. canti spacing: can I use modern canti / v brakes or will they be narrow only allowing a limited choice of cantis?
   
2. seatpost size?
   
3. 1" or 1⅛"?
   
4. is 1⅛" threaded cross compatible with 1⅛" threadless/ahead? ie can I just get a 1⅛" threadless fork and a new headset?
   
5. wheel spacing? Anything funny?
   
6. Any other funny business? 26" wheels that aren't 26" and won't take easily available tyres, etc?
   
   

Cheers