Well go back and just read what Ed writes. You don't have to read every responce as some of it is trivial and arguing over pointless details as you brought out. Ed sums this up pretty well and you should have a good idea of the problems associated with mixing after reading his posts. As a self described begginer, almost everyone would tell you to stick with a single species tank, as an understanding of each species habits is benefitial should one take on the complexity of a multi-species tank. But read through all of Ed's posts, I think you will enjoy what you learn.