I'm a little bad in english but I try to answer you !
1) We fixed a number of players for a match at 4 !!! So this is the minimum of players by Match !
Somes teams dispose enter them to fix another number of players ! It is of that come 6
!
However you can play for example 5 vs 8 player provided that the number is a minimum of 4 !
2) Maps must be choose in the Pack Map ! You choose 3 map for a match and you can't choose them again for another match !
If a same map is choose by the two teams: they must arrange together to choose differents maps !
3) Anyone of YOUR team can play the match (normal ^^ ) from the beginning of the match to the end ! But let us recommand that you can choose substitutes for a match whose numbers of players is fixed ! More: a player can't joint "in the middle" of the match !
So I hope to have answered to your questions !
Good Luck for the tournament