>>39098437/umami/ really doesn't exist outside of the basic concept but I think they tend more towards luring people that dont have families to be missed so as to not draw suspicion. The /umami/ architects probably wouldn't operate on the island, more as individuals with their own plump wives that they occasionally surprise with a bit more meat on their plate than usual, they'd be very careful not to do anything that arises suspicion since they wont have the support of any nearby architects or meatheads if they get caught.
If snagging a hag from /hag/ is too difficult, they'd just not do it.