I haven't looked into inter-species relationships for halo before so I can not make a clear statement about it. I do know it exists in the Mass Effect games and they do have certain rules when dealing with different species. I will need to further look into it for halo if it does exist somewhere, otherwise I would assume it would have to be similar to the Mass Effect laws (especially the one about being unable to create any sort of hybrids) about inter-species relations. Personally I have nothing wrong with the idea itself as I practice it in the M.E games. Definitely need to look into more research on it and if it does not exist I will find a way to come up with a way to make it work in the future in case others have a curious side toward it as well.