I would definitely introduce him to others just saying the Ll as an L. But at home I might pronounce it correctly for fun.
I'm just not sure what my favorite nn is. I went to high school with a
Llewellyn who went by
Lynn (spelled it that way for some reason). I think Llelo is really cute for a little boy though. People will call your kid whatever you introduce them as, so I'm not concerned with it not being that intuitive.
How is Fiametta said if it's not fee-a-MET-a? Fia is super cute though. :)