According to that mod, you just add files to one of the preload_ vpp files. Don't know why i couldn't get my attempts to work, before. Maybe i'll start trying again.
As for the player's team, i forget what the valid teams are (it's in one of the xtbl files), but here's STAG:
set_team(LOCAL_PLAYER, "STAG")
Or, to go back to the Saints, it's this:
set_team(LOCAL_PLAYER, "Playas")
When you're done with the altered model, i believe this clears it.
customization_item_revert( )
customization_restore_player_rig( )