I'm sorry that you may have rec'd less than accurate info, guppy. No sweat. You're here on a positive note and certainly willing to participate. That's great!
I don't even know what to say about 'black-line pikes' and 'slender pikes'. I have no idea what species that refers to. No matter. Pikes species are each so unique that interbreeding is the last thing anyone has to be concerned with. Their individual breeding cues and coloration (both neutral and breeding) will enable several species of pike to inhabit same body of water with no danger of interbreeding.
In regards to last post, Cr. lepidota occur literally 2000 + miles south from Cr. alta habitat. I doubt they've met.
Cr. scotti is indeed a pike, while the facetum species mentioned is a chanchito, Cichlasoma facetum. I know they've met in the wild-I've imported both species for years from both Uruguay and Argentina. However, I'm sure they never gotten it on with each other...