You dont find kelp crab or neem in garden or hydro stores normally. Kelp comes from feed stores. Gardeners using kelp is nothing compared to the amount of kelp people feed horses, chickens, pigs etc. Id honestly be suprised if a feed store didnt have it or couldnt get it in. And the ocean usualy grows it. And it grows HUGE FAST.
Crabs also live in the ocean. I cant remember a time walking thr beach and not finding crab shells, oyster shells, mussel shells etc.
For neem order some comfrey bocking 14 roots and get them planted. Feed heavily on the ferments and use that to replace your neem seed meal.
There ya go:)
Ps. We cant even get a permit to get neem up here. Its too good. Itll ruin the gardening storesXD same reason kelp aint in garden stores.