Yes, level & # of allies are the only factors, the other stuff doesn't matter as far as the battle list goes. The population numbers does affect the span you can see or be seen at though. For example most players can usually only see their level and maybe 1 level above and 1 level below but as you progress the higher level players don't have full battle lists so they can see further down thereby filling their list with lower level players.
For example--I'm at level 98 and can see down to level 70 but a level 70 player likely only sees level 69-71 give or take. Their bracket is more full so they dont see as big a variance but mine is not so I see more variety. Hope that helps.