I think they kind of cheated. It's an awfully long article for being missing on critical details, but that's par for the course for what passes as journalism these days.
Dingwall ABI, Yamaha BB1025X, 60th P-Bass, Select J-Bass, Geddy Lee J-Bass
Eugenio Upright, Viking Bari, Select Strat, Select Tele, LP 57 Gold Top
Yamaha WX5, Hammond XK1c, Moog Voyager, DSI Prophet12