Absolute minimum 36" I'd say. preferably 48". purely because they are all bottom dwellers except the butterfly.
Pictus cats need a minimum of a 36" tank.
Redtails need 30" but more if there are other active bottom dwellers.
keyholes need 24".
I have a redtail in my 96l with some other bottom dwellers - a very small (2-inch) starcrown pleco, a weatherfish and a Bolivian ram. The redtail ignores all of them except the ram, which it occassionally chases. If a fish looks even vaguely like a redtail, it will get chased at least sometimes. In this case it would probably mean some conflict with the keyholes, and maybe the pictus. The bigger the tank, the less conflict.
Also with that selection of large bottom-dwellers you would quickly max out the bioload in a 36" tank, which would mean a very limited choice for any midwater fish. Be sure to use plenty of wood, plants etc to break up the fish's line of sight and provide hiding places.
:OT: BTW how's the newt?