Yes, Olrox is singing "Summer Breeze" by Seals and Crofts. If I had to guess, he's probably actually singing the Type O Negative cover, just because.

They did do a new soundtrack for Nosferatu, so there's a bit of connection there.

Of course, neither version of that song was out in the 1700s, so we'll just have to ignore that little bit of a continuity error. Personally, as with so many things, I just blame this on Angel affecting the time stream.
 
    

When evil spreads across the land, and darkness rises and the monsters roam. When the creatures of the night make beautiful music, and the things that go bump in the night go bump with greater enthusiasm. When the world is in peril and is in need of a hero...

These guys are, sadly, the best the world can hope for. These are the adventures of the heroes of CVRPG. They mean well, they try hard, and occasionally they do the impossible...

They actually do something heroic.