Dear pacuboy,
I think you meant to say polypterus rather than "regular polygon", and I think that is doesn't hurt any individual to research plenty before a purchase. Seeing as that your 55 gallon tank right now has just over 100 inches of fish, and that you also have 15 more inches of fish coming Saturday, I strongly suggest that you leave any of your bichir choices out of your fish tank. Even if you are getting rid of all of those tetras, you will still have about 68 inches in that tank! With this being calculated, I can now state without any hesitation, that you should not add any single type of fish to your tank. How about supplying us here at TFF with some pictures of your setups? I read somewhere that you also have a 120 gallon with pacus and stuff, too. I'd like to see your tanks (or at least hear about them); they sound very busy. So, finally, my answer to your question (Can the bichir live with all those fish?) is no it cannot, and I am surprised that you can live with all those fish in that tank.
Sincerely,
Wonderboy