Sounds like the UFCW won't step in to help on that front unless the union is voted on? Should we just find a labor lawyer instead? Or is this just a risk we have to take once we start advocating in the open?

UFCW would most likely help you file ULP charges and navigate that process before an election (especially if you had already signed a card) but American labor law is basically pointless and you'd still be out of a job until you could prove to the board that you were fired for protected activity which can take months or even years if you can prove it at all whether or not you have a large union helping you. Also usually labor lawyers offer services cheaply or freely to working people. Sometimes UFCW will hire workers that get fired but from what I've heard working for UFCW is horrific so not sure I would recommend.

If you have a worker center or maybe a labor education center near you they might be able to help guide you and put you in touch with a lawyer.

As for organizing independently you're going to be doing the same thing for the most part that you would with a large union (assuming you work through the NLRB). Build a committee, map the store, get people to sign cards, petition the NLRB, win an election, and negotiate a contract. I think you'd need to have some sort of charter and officers at some point and if you're handling more than a few hundred dollars as the union you'll need to incorporate as a 501c(5) but those things aren't as complex as they might seem.