Yes a convict can breed with a pink convict... more males than females will probably end up resulting in world war 3. Just because you have a male and a female doesn't mean they will breed. It is highly likely due to them not actually being fussy and their willingness to breed.
They are literally identical. Just a color difference. To my knowledge there are no behavior differences or anything of that sort. They are just as aggressive and just as willing to breed like rabbits. I have a pink male and a black female whose fry just started swimming. You can see them in my thread dubbed "It's been a while".
I believe they're just a colour morph... Their cousins such as HRP's, Myrnae's, Jade Eyeds etc are usually less aggressive, but most Cichlids are evil when spawning.
In my experience (I've probably had 8 breeding pairs over my life) they aren't very picky and will pair up with just about any other convict. I don't foresee it as being an issue. Just pop him in and see what happens.