Dietary probs do look likely, considering all the cracks on Apache's, although interestingly there seems to be none on the left fore. Yes, getting too much/too rich etc, can cause laminitis. Yes, lacking or imbalanced nutrition can cause 'shelly' feet.
Laminitis is not necessarily obvious to the untrained eye and early or 'sub clinical' or 'low grade' - whatever you want to call it - may be difficult or impossible to see even for knowledgeable people. It is quite simply inflammation of the laminae, which causes damage, leading to weakness or complete breakdown of the connection between wall & P3. It is generally, but not always, diet related. It doesn't only effect fat ponies(tho those are generally higher risk) - any type or build can be at risk. It doesn't always come on with obvious lameness, and the 'stance' is generally only seen in acute or chronic cases. It doesn't necessarily mean P3 is 'rotated' in relation to the hoof walls, or that P3 has 'dropped' lower in the hoof capsule, causing flat, thin soles, although those 'symptoms' are what is commonly referred to as 'founder'... although some don't even call it founder without a significant degree of 'rotation'.
So... you can't necessarily tell, at least until the 'disease' becomes more chronic or acute, when a vet exam/xrays can show the degree of damage. Once the weakened laminae have grown down to the ground level, you may see evidence in the white line. Flaring & stretching can be a result of lami. So... it's far better to just always manage a horse in order to avoid or minimise the risk of lami, rather than waiting for any 'symptoms'.
Didn't get a chance to look at/comment on pics before. There is a fair amount of flaring all round, esp the outsides of Apache's. It *appears* that there is also some m/l imbalance here & there - hairlines wavy & uneven, etc. This could be just the pics/angle/way the horse is standing tho or may be a long term thing that may not be due to current farriery. What's with the horizontal crack on Sammy's off rear? Is it an abscess fault that burst on the coronet or is it one of those cuts that some farriers make in the attempt to head off a grass crack? If latter, I wouldn't personally allow my farrier to do this, but rather address the imbalances & flares more effectively, so any cracks will just grow out.
As mentioned, take my comments only as food for thought, as aside from it being just my opinion, I can't give you anything like accurate ideas based on the info I have. There are just so many factors too. Eg. I don't know how old the horses, how long you've had them, how they're fed/managed, etc, how these feet looked before the current farrier, how long you've used him, immediately before & after trim pics, even how they look standing square on a firm level surface or from underneath, bar those 2 pics, etc. With regard to pics, did I mention Good Hoof Photos - How to take Good Hoof Photos
? Giving as much info as possible will get you more accurate critiques, but even with the best info & pics, remember it's still beyond the realm of a remote, forum based 'consult' to be accurate.... which is one reason why I don't like people charging for it!