Booking at legit booking joints will always require you to pay upfront. You can bring the girl back on the spot after you paid. If you have things to do, can tell the okt to only send the girl at X hours. Some will ask for taxi fares for the girl though. It does help to get the okt number in case the girl comes late, or gives you problem.
Yes, if hotel room, usually is one room per dick. (I can't imagine why you would want to share room. I regard having sex with a girl as something very personal...
) Usually, Indonesian girls are not that into 3p, irregardless 2m1f or 1m2f. We do, however, booked apartment before that comes with 2 bedroom and a living room. Girls are OK with this.
HTH.