It depends on your goal.. split ventrals may not be ideal if you are showing, or planning to sell to breeders.. but to the average person it's not a big deal.
What I'm more curious about is his feathering in his tail fin (which looks to be pretty close, if not 180 in those last pictures) - has he been in with a female that took off most of his fins, or is it feathered like that normally?
If it's feathered like that normally then that is what you should be concerned about more than the ventrals.. the ventrals are nothing compared to feather/rose tails. Breeding feather/rose tails you are going to guarantee most of the spawn will need to be culled as it produces deformed fins, scales, body in most of the fry. It's a mutated gene that brings out a lot of trouble in offspring.
If you have something really dark to place behind the tank, and take a side view picture of him, can see it better. Has to be a dark, solid color.. otherwise you won't get an accurate assessment.
As mentioned before, he does have a spooned topline.
As for the female - it's not that easy to find an HM female that is a full 180 spread without spending a pretty penny.. so that isn't as big of a deal - in a normal HMxHM spawn you will get a good number of deltas. It's just with a full 180 female the HMs have a better chance at being better looking, tail wise.
Now.. are they PKs? He has rather short fins.. but not shaped like a PK (and if he is long finned, how old is he? As he doesn't seem fully developed. And the female looks PK judging by her anal fin, which is rather short compared to a long finned HM.
As for what you will get color wise.. it's a toss up. Kind of all over the place with those two..
I suggest if he proves not to be a rose/feather tail (need that black background side view pic) then I would look for a female that would compliment him more - can work out the split ventrals eventually down the line.. but look for a marbled girl similar to him, or a solid black or white even.. but that is just my personal preference.