Do you have a limit of participants for one lottery?
I think there will be no limit, the more people, the better
And what minimum of players is needed for the game to be launched?
I am not sure, but i think that 0.1 eth is enough.
There is no sense to set up lower limit for draw, it is not that interesting, comission fee,etc
The percentage should be such that people were interested and there was some excitement