IMO the Puffer will be Hit & Miss, it is a combination you want to keep an eye on. The Puffer can nip at the lion in return the lion can sting the puffer. I have heard stories of this going both ways........ I do it in my 300g but watch the combo......
It is not recommended to place Lions with eels, lions rest on rocks and can become an easy target for eels. Again I have read stories of eels going after lions and lions stinging eels, Just a bad combination.....
My experience in adding a White face Moray to my tank one time, by that evening it was going after one of my dwarfs, trying to eat it and leaving bite marks. I took the eel back and my dwarf recovered, for me this is a combination I will not try again.....
Kaye