The word "Balrog" in Tolkien's Elvish (Sindarin, specifically) means "Demon of Might"; bal means "power" while rog means "demon."
I can't say for sure that the name form may or may not have been inspired a bit by Balor, but I wouldn't be surprised if it's just the end result of creating words from his invented language.
As for Gruumsh/Balor, & thus the orcs as Fomorians; that has a bit of a possibility. Then again, Gruumsh could be seen as a sort of Odin-figure (with his son as a Thor-like figure). Or, to take it to another extent, Tolkien's imagery sort of creeps into the orc pantheon as well (at least with the symbols): the Eye of Gruumsh can be compared to the Eye of Sauron; the symbol of the orcish death & disease god can be compared to the White Hand of Saruman. But then again, it's all about how much you want to read into things.