I have diamond doves, button quail, star finches, silverbill finches, spice finches and gouldian finches in a large indoor avairy. They do fine together, I have a variety of perches at different levels, attached some fake ivy along the the larges middle perch and up the sides and keep a couple cardboard "huts" in the bottom for the button quail, they can hide in them or behind them. (I toss em when they get poopy and make new ones) My DH also made a large swinging perch from a branch, drilled to accomodate two differnt size dowels to make three perches, the finches and doves love that one. I do have three small wicker baskets tucked under the ivy but remove any eggs. I think it helps that there are plenty of separate spaces, and some hiding spaces too.
Select finches that are compatable with each other, that have simialiar feeding requirements. I found a chart on line that was a big help, look out for breeds that are too territorial or get aggressive during breeding season.
I do have several feeding stations, on the ground and at mid-level I clamp millet sprays. I recently decided I want a seed feeder higher up and am deciding what to do about that. I also feed a variety of fresh foods and homemade egg food. I add some of my chickens layer crumbles (crushed) to my egg food for the quail but figure it can't hurt the others.
My friend mentioned my aviary feels like watching an aquarium with activity at every level.