The top ones look the most Heaton to me. Lower left might be Ravenswood and the lower right might be Alley, but I think some of these could go a few directions.
Well, there is everything from soup to nuts in this lot, which spans many, many, years of marble production. All I can say is that I hope you find some good ones!
You're on track, left and lower are Buttermilk variants and the upper is a Superior. The best Buttermilks have less white showing but these are really great marbles, regardless.
Huh, I didn't even notice the blue until I enlarged the photo - i was thinking it was base showing through white or something - you know how it can look sometimes.
It still looks foreign to me, I don't recognize it as anything American.