Looking for logistics help

Currently I'm in the early stages of an idea that would make the Black sisters the same age as the Golden trio. This leaves some gaps to be filled however.

I plan on making Voldemort's right hand Pyrites (the cut character that never made it into the book) and making him a type of mad scientist character.

But I also need a Lucius stand in. It COULD be Cygnus but I hesitate on that.

Ideas? Anything I missed?