Yes they will cross, but this is something that you do not want to do. Crossing species is frowned upon in the hobby, it is important to keep the species clean and free from crosses. No one is interested in a cross, they are just considered mutts. Right now these west African Riverenes are very popular and while it seems they are readily available, they are not. It is very risky trying to collect these fish right now. The countries are not safe, and the governments are shakey, many of these remote areas are ran by locals radicals, it is a very scary situation. Since imports are not consistent, it is very important that if we want to continue working with these fish in the hobby that we insure they are bred true.
You should be able to find the correct mates for your kribs, just take a look at these two websites and hopefully you can find a breeder that can help you out.
Please don't cross your fish it is up to us as responsible hobbyists to make sure this doesn't happen in our tanks.