Small town means small time thievery. Can't ever tell why people steal bonsai. I'd bet these idiots see something they can sell quickly for a few bucks. They're opportunistic thieves, which are a distinct category of bonsai thieves, as opposed to those who target certain trees.
Cragislist, yard sales and farm markets, or just personal sales to people they know are the likely fate of these. Not much you can do to get them back. I'd file a police report just for the record. If you still have receipts for them and they total more than $1000 (things add up, pots included also), the theft could be a felony. Below that, it's probably only petty theft. They know you grow bonsai. You replace these, they could be back for more.
FWIW, I would relocate all your trees to the backyard (preferably a fenced backyard). That mostly eliminates these kinds of "look at those, let's come back tonight and take them" kinds of thefts.