Why did you get rid of your eels? Unless it was a tesselata or something huge you should be ok with lions and eels.
Lions have more venomous spines than their dorsals. Not sure exactly how many but some of the first spines on almost each fin is venomous, you can see which ones on a big lion.
Also I have to disagree with the vast majority regarding "dogface" or arothron puffers nipping the fins of lions. I have said it many times and I'll say it again, I have a large lion that has been housed with numerous, supposed "fin nippers".....and never have any of them harmed my lion. ACTUALLY I have seen large angels pick at the spines of other lions, not puffers.
Oh.....have never seen a problem with lions' spines and bags or transport. They always seem to just fold up against their body.