Hi SamAli
I'm new to it too so I may not be the best person to answer but I'll give it a shot.
I think Phyl had a good answer to the MLS vs MLIS debate and I agree that the information piece is very important nowadays.
As for getting two different Masters, I'm not sure that's necessary, most MLIS programs have concentrations to get a little bit more specialized and if you're thinking History, I know there are a few schools that offer a dual degree in librarianship and history, would probably take a shorter time than getting the 2 degrees separately.
You definitely have more library experience than me so I'd say you're doing pretty good haha
Sorry, I don't have more for you, hopefully you'll get more responses.
Good luck!
-Laura