Okay, after you're done, I'll read it over to see if it's could possibly be accepted. I'm not the GM or anything (even though I was offered to be, but I said no), I still have been around for awhile. xD
Like Supervegeta said, blood bending is connected to Water bending (Katara can use blood bending due to blood having water inside) and sand bending is connected to Earth bending due to it being eroded earth. Same as how metal bending is connected to Earth bending due to it being refined earth (although, if your character is a metal bending, then Toph wouldn't be the first metal bender). xD
Supervegeta did talk about it on the RP, though, if you've seen it.