I played the KALA fretless and liked it alot! Then in addition to the instruments you introduce here, Alex, there’s BLACKSTAR 🇬🇧 w\ their Carry-on mini electric bass guitar 🎸 I play one, it’s a great instrument!
I guess I can say this is a pet peeve of mine, I'm a stickler about the designation. To me the proper generic term is bass uke, just like the other uke designations; soprano uke, concert uke, tenor uke, baritone uke. Uke bass or ukulele bass is not consistent. I will only call the Kala a U-Bass because that's their specific model name. Since mid 2014, I've gone through 54 bass ukes/mini bass guitars, and now my collection will amount to fourteen RondoMusic Hadean violin/Hofner style copies. Let me add that Kala licensed the bass uke design from Owen Holt of Road Toad Music, which is why there's a toad on the faceplate of the Kala U-Bass.