Congrats! Like I said before, keep an eye on your rams. When the bichirs get a certain size, the rams no longer look like tankmates... they look like lunch!
I got the last of my butterflies about a month and a half ago and only 3 of them will take food from my fingers... the biggest three! The other 2 males steer clear unless there is no hand in sight. I think it really depends on the fish.
Oh, and do you know if you have males or females? If you post pics, I could probably tell you.