You could either keep the tank up and running with a few fish in it. When the new fish arive, the other go over to another tank. You can then add new ones, or decide which fish move back in the q-tank.
Another option is to get a mini-penguin filter, or I guess any filter would do. Keep it on your main tank. When the new fish go into the q-tank, move that filter over. The bacteria levels should be more than enough, unless your fish load in your q-tank is a lot.
I usually have some choice guppys and algae eaters in the tank. I added 10 Ruby barbs(small ones), and didn't get any ammonia. I use an old saltwater wetdry HOB. *thumbsup2*