Battles of the late Third Age

[Gwaihir the Windlord]

Possibly, Finwe. But there's nothing to say any way.

I always thought that the Balrog was "unearthed" by the Dwarves who "delved too deep" for the mithril.

Yes, it was awoken by the Dwarves that had lived there in the time of Eregion -- not Balin's little group, who went to reclaim their ancient halls. (Check up on your ME history [img]smilies/smile.gif[/img])