I love my African butterfly, they are so cool too watch eat. 3 inches long is a good size african butterfly to start out with.
The elephant nose is an interesting fish, I have come so close to buying one, but instead bought a Black Ghost Knife instead, but they are very similar. The elephantnose will need good water quality, nothing crazy good, just make sure that you keep up with water changes. Keep in mind that the elephantnose fish don't have scales but have more of a "skin". This makes it very hard to medicate the tank with many types of meds because it can harm them. Should be cool too watch the elephant and the butterfly, you may want to look into a mid level dweller? Such as a Needlefish (NOT NEEDLENOSE GAR) NOTE:Needlefish must be fed live food like rosies. I have kept mine with my African Butterfly and they get along fine. The needlefish is a great addition to a tank laking midlevel dwellers because they are always visible and give you something to look at since they don't hide. Something to think about as far as lighting- I would think about putting an actinic or 50/50 bulb on your tank to bring the lighting to a more subdude level, since the elephantnose will like it darker and my African Butterfly and my needlefish are more active with my actinic bulb on my tank. Have fun with your good selection of oddballs