By Dinosaur Eel I am assuming you mean Polypterus senegal, as that's what Petsmart and other chain-stores sell them as. You may want to get into the habit of calling it a senegal or a bichir, as referring to it as an eel is going to confuse a lot of people. It's not an eel whatsoever.
I don't think your frog will get much bigger, whereas the Bichir will continue to grow for awhile yet, albeit slowly.
The way I have seen those african frogs rest on the bottom... I wouldn't trust one with my bichirs. If they could catch it, they would eat it.
I'd say no to the combination but maybe someone here has actually tried it and has better advice. Both of them are fairly slow bottom-dwellers so you may be able to make it work.