...following up on this thread -- I finally bought a bike!
I bought a 6-speed Brompton off Craigslist. It's older, early 2000s, and has a tad of rust on some of the bolts, and could use a tune-up, but it rides great. So I've started watching Youtube videos on how to remove the rear tire, in the event of a flat, and basic maintenance tips, etc.
Thanks for all the input in helping inform this decision -- so many awesome bikes to choose from.