Hey Joe,
(yes, trite and most likely worn out by now but, I just can't help myslef)
You can find the Minwax filler at any Lowes,HD etc - it's with all of the other wood fillers.
As for stripping the finish - depending on just what Bach used for paint stripping might be a hellish nightmare
Modern finishes are made to be durable and therefore can be real bitch to strip. Take a look at the ReRanch site and there will be many threads about stripping poly finishes - aircraft stripper, heat guns etc.
As for the old finish showing through this is a positive for old Fenders. Back in the day Fender was real quick to grab a burst body and shoot a custom color over it. Years later the colors wear to reveal what's under the new finish. Me, myself, I'd prep the old and shoot the new color