If you are planning on being in the South Florida area please PM me for my email address. I'm in Fort Lauderdale, and may be able to help you out with sources locally for the screws, drills, taps, etc., as well as forwarders for anything you can't carry out under "spares".
I like the suggestion someone made about sticking to stainless, you'll be happy about that.
I might suggest you standardize on metric for simplicity's sake, as the taps and dies are readily available, and drill bits can be interpolated from letter/number sizes. If not, standardize on fractional (UNC/UNF) for easy availability across the board.
In the meantime, go around to all the repair shops down where you are and see if there's chunks of brass or bronze (or stainless, if you're brave) prop shafting, broken propellers (for the hubs), and damaged large nuts that could be used as machining stock. I remember there always being that sort of stuff laying about when I spent time in the Bahamas.