The toes look a tad "square" to me. Not the wall, as in the bevel, but in the overall shape of the footprint. Make sure you don't leave any kind of "corner" at the toes. If you over shorten the very front of the toe, and in effect make a square toe, it tends to split right up the front, espeially if they have ANY weakness going on there, *ahem....previous founder, or damaged tip of the coffin bone from horrible shoeing* anyways, the hoof at ground level should match the shape at the hairline...round.Another little tid-bit--sometimes a horse will have an eroded or incomplete coffin bone at the tip. If the tip isn't there, there's a "blip" (I am totally making up that term, btw) in the lamina, so there's less "velcro" and it looks like a constant streteched white line or even appears as WLD ,and it is a weak spot that opens the door for fungus, but may not be infected, yet still have the spot. It is the same in shod horses, you just don't see it on them.
How do you know if your horse has this "blip"? Pick up the hoof, check out the toe where that crack is. If there is a groove/notch/triangle at the tip of the toe, where wall meets sole, thats just that littls spot, and the toe tends to crack up to the hairline if you don't keep up on the trims, and the foot is prone to being squared off with wear, that could be what you are seeing. Soooo....just round off the corners, keep up on the trims and a preventative soak in ACV once every couple of weeks should do it. Apply a sealer during the wet season or when it's fluctuating from wet to dry, and that sould help a lot.
The quarter crack, is just breaking off to where it wants to be trimmed. Not pretty, and has the potential to crack, but use it as a guide next time you trim! Just smooth off the wall, scallop it to being a tad shorter than the rest of the wall.