Maybe my recall is inaccurate, it was forty years ago. If it wasn't Columbus, I'd guess at Antoria and I'm not certain it was a Ripper copy not a Grabber. Either way it seemed an OK instrument in those days.
Playing open strings is good. It's four notes that are available in any position.
Especially on a fretless where it's four notes that are always available and also in tune.
(Obviously more notes on a fiver, etc.)
Me too but also Mamas and Papas, Turtles, The Assocation, Fifth Dimension, etc, in fact many West Coast/Los Angeles session players. Although some e.g. Carol Kaye were using a Precision.
Fender Jazz with flats (preferably GHS Precision Flats in my view) and played with a heavy pick over the neck pickup is a 1960s thing and not just TV themes.
If it's just a couple of bases in cases, for a few months, I'd ask musician friends to look after them for me ... they usually don't mind too much having an extra instrument lying aound.