Drummin The Boogie is said to be N/N, but i don't know. I say if you're not totally in love with him to count him out, unless his owners could provide you with a copy of his test results.
I know nothing about breeding a HUS to a cutter, so I cannot tell you how they will come out.
If you definitely want color, i don't think Scenic Zipaloot is the guy for your mare :)
I'm not fond of how Mr Tramp-The Living Legend is standing or his back and neck. Though his color is pretty, i don't like his conformation. And i'm going to assume he's like that all the time or else I'd think they'd use a better picture of him
I would like to see more pictures of Rock Four so i can see his coloring better and without a saddle on. And while it does say his foals of size, it has nothing about color.
I too am a little curious as to why MAXS IMPULSIVE COLOR is for sale. I just think that's a little odd. What would happen if you want to use him as a stud, but he got sold and gelded?
I'm not sure if this helps, but that's my opinion. I would ask though, if you could get a copy of Boogie's test results, that way you'll know for sure if he is NN or not.