Ok, for the OP, I'm not going to comment on your post (sorry). Loosie et al have pretty much said it all so I'm not going to jump in with more of the same (but Lord, please take care of those heels).
The only reason I'm bothering to post is to comment on White Line. White Line disease is an infection. No diet in the world is going to kill that bacteria. Horses on wonderfully healthy diets have not only gotten white line, but more importantly, have had it spread and get worse. According to the "diet will fix it" concept that couldn't have happened. It's the same as saying that diet will cause or fix thrush.
Loosie and I have beat this to death on other threads, but I'll say it again. While no one who has spent much time dealing with horses (especially their feet) is going to dispute that diet can be a major factor in the health of the equine foot (or at least they shouldn't....although there are some "professionals" who've never seemed to "get it"), the greatest diet in the world will not prevent WLD that is contracted as a result club foot, a long toe, a nail hole (my personal worst case, but I won't get into the woes or reason why horses should not be shod.... that's a different topic that even Xenophon covered about 2500 years ago) or the like.
Diet won't prevent it in any of those sort of cases (which tend to be too common) and diet is not capable of fixing it. If it would we'd all be doing that. In fact, if that was the case, WLD would never be an issue with horses that are on a healthy diet. So the cases that exist with horses that are on a healthy diet could not exist (but clearly they do).
Diet is crucial to good equine foot health, but it isn't a cure all by any stretch of the imagination. It can't "fix" infected areas...unless it somehow causes the equine to create it's own infection fighting, bacteria killing substance that cures the condition...but then if that were the case then no horse on a good diet could never get these infections (so we can stop worrying about it being caused by long toes, etc... and if they do get it don't worry about treating it, since the diet will cure it
....I wish I'd know about all this earlier.....would have saved a lot of work). We know that's not the case, because they have gotten it while on a healthy diet and it doesn't "fix itself".
I've also yet to see any study that shows that proper diet will prevent a horse from getting WLD or cure it (diet can't prevent the bacteria from creating the disease). Unless they've come out with some GMO strain of oats with a bacteria killing trait that gets into the horses system and eventually reaches the foot where it kills the offending bacteria....but then that results in a less than healthy diet that could lead to more foot issues, since grains are bad for horses...that bacterial killing feature of the GMO would also likely attack the bacterial in the horse's hindgut needed to digest fiber....but that's a different topic too