Because of his red comb, sometimes you can have lighter eyes. If his eyes are nice and dark and round, then he's good to go! Really he's a pretty good looking boy, I don't think you have much to worry about. He has some faults, but with careful breeding, you can offset those! Yeah, he needs to go with either a blue or splash. But you can use black, too. You'll just get blues, is all. (if she throws some splash babies, then you know she's not a true black) But likely she is, since you know she came out of a black X black pen-- which means all blue babies. Blue X Splash will then give you BOTH blues and splash, so you'll get more colors. I wouldn't bother to breed him with grey or partridge, there just isn't any point in it. If grey and partridge is something you want to get into, I'd get a counterpart for them in the same color so you can work with them. Since this is a breeding and genetics thread, no one is going to be enthusiastic about anyone just mixing up colors.
I really do think you have a good start here. The only down side that might happen is that your all-blues could be VERY dark and look close to black. But those blues make the best birds to bring back color into a diluted splash, so they are worth something too.