The yellow and kole might fight...might not.The hippo and yellow really get too large for an 80 gal. tank though.The kole and angel would be fine.The tank needs to be mature though for these two fish..over 10 months.
the tank is at exactly 1 year old and we are planning on getting a bigger tank when the money is more readily available. The yellow tang was purchased last week and is really small.
My suggestion then,is to keep only the 1 tang until you do the upgrade.Tangs need swimming space,even though it is small.Yellows can become very territorial,and bully new arrivals.
ya you are right, yellow are very territorial and do need lots or room to swim... a good rule of thumb to use when it comes to tangs and other species as well is that if a fish is the same body shape as another they might not get along. espcially with tangs.