Thank you, Adri, so well put! This was the conclusion I came to as well, but then genetics is so full of exceptions to the rules...
There has been some additional concern brought up by Gliderguyva's wife in the past. She is a veterinarian and before that did research with genetics(?) I'm sorry, I know I am botching exactly what she did. She said that likely the leu gene did carry genetic defects moreso than a grey or wf simply because it is not found in the wild and that they did in fact have a chance of being carried right on the color gene and that it may not be noticed until several generations of leu/leu because it could be a progressive gene (most traits are not single genes that work nicely in a punnett square). My question, and it was never answered, was if those defects (if there turns out to be any) could be bred out in one generation by simply crossing to a non-leu even if, worst case scenario, it was a progressive gene that did not get noticed until several generations of leu/leu breeding.
Regardless, by those principals, plats are not found in the wild either, so all of this would presumably hold true for them as well.
It is so hard. We are all amatures, really (including me; I know its going to be humbling when I hear what parts I botched up in my attempted paraphrase of this professional's prior input), and we are deciding the genetic future of these animals. In nature there is an intricate system that decides it and does it beautifully. There is no scientist that has ever existed that fully understands that system; it is so complex, we cannot pretend we do. When it comes to genetics there are so many layers; if we are honest we are all working with a very small piece of the puzzle. We all realize how important this is, and often we take a very strong stand because of this.
I think it is really important that we embrace our amateurism. Get as much info as we can, do the absolute best we can for our animals (and, yes, there are reasons that breeding leu/leu or plat/plat could be beneficial) and view others who have made alternate decisions as amateurs like us also trying the best with the little info they have to do the best for their babies.
This thread has been a great start at that; getting to the information and not getting sidetracked with opinions. Thank you, everyone, for such a nutritious thread!