I've seen weird grafts. Never quite that weird. The first two look like the grafts weren't set straight and fully in contact, so the graft joint had to fully close up a gapped wound. The bottom one looks ok... the scion perhaps was oversized to the stock, but not bad. Since you already bought them, if the tops look good (strong buds and healthy cambium to the top of the tree), should be ok. If the nursery has a tree guarantee, then so much the better, but looks ok from my experience.

I wouldn't be worried about infection...these are graft unions, last one showing incompatibility, root & scion, [bulging] should be staked, otherwise might snap in a strong wind. Second tree seems a bad graft.