However, IIRC the Hadeans don't come with the best strings installed and I'd rather not have to fool with changing out the strings right off the bat.
Hadeans come with fine strings, though they may not be what you want - especially if your goal is rock bass. There are several types of strings for Ubasses and it's personal preference what you like. The classic uke bass strings are flooby synthetic rubber (Thunderguts, Pahoehoe, etc.) which feel weird but give a great sound - they're as close to an upright sound as you can get without an upright. More modernly there are a lot of options for round- and flat-wound strings that will give more of a bass guitar feel and sound.
In general you want to buy a bass with the type of strings that you're going to stick with - the types are sufficiently different (flooby strings are very large in diameter) that you may need to modify the bass to switch types. Switching the nut is easy, but modifying or moving the bridge can be a major project.
I love the sound of the rubber strings and have them on my Hadean solid-body and my GoldTone acoustic. If your goal is rock-bass then look for one with round-wounds.
I was thinking the same thing, that is after playing enough on my own to feel comfortable with root and 5th I would start at the group, unplugged, just to see if I could keep up -- I'm assuming that this means that I should start with an acoustic UBass. Then at some point I would add an amp but certainly not until I felt like I would be contributing as opposed to detracting.
Just playing roots is valuable and relatively easy. The hard part for me is that chord+lyric sheets are often ambiguous as to timing - do you play a specific chord for one bar? two? half? If you're not familiar with the music (or if the group isn't) it can be hard to keep on track with changes, and it's a skill to keep going and stay on the beat even if you hit the wrong note. I've been going through the songbooks and annotating them so they're easier to follow.
Acoustically, u-basses are pretty much non-entities. They are very quiet, and you will need amplification to be heard. I like my acoustic because I can just grab it off of the wall and play a bit without having to plug in. Even though it's loud for a UBass (it's 25" guitar scale, so a bit bigger) it's not audible in a group.
I definitely would not want to have to tinker on my first bass.
Don't get a cheap one, and watch your return policy. The pickups on cheap acoustic basses are notoriously flaky. They're not hard to tinker with, but it's likely they'll need tinkering.
it also sounds like there are really only two choices (Kala or Hadean) so that helps.
There are many other choices (sorry - not helpful
). Most of the typical cheap Chinese brands (Donner, Kmise, Aklot, etc) have a bass these days. They're probably all comparable. Be careful of Luna - they have a "bass" that is tuned an octave higher than normal to a guitar octave.
If you don't need to restrict yourself to uke-scale (mostly 20", but Kala--the owners of the UBass trademark--make some 23") there are very good options in the 23"-25" scale from Ohana, GoldTone, Taylor, Ibanez, etc.
Locally, several uke-group bass players have these, and a Uke festival last year had Ohanas as loaners for the UBass classes. I've not seen anybody turn one away (ok - one grade 4 kid thought it was dumb to come to a uke group without a uke. He was only there because Mom wanted to play), Being acoustic my flooby-stringed GoldTone 25 feels more ukey than my bright blue, solid-body Hadean with 20" flooby strings.
The basic concept is the same as playing fretless bass guitar just scaled way way down.
Most UBasses are fretted. The best ones are fretless
(probably not for rock bass). Otherwise correct: UBass are much more bass than ukulele. Bass lessons and techniques apply -
Scott's Bass Lessons is great.
TalkingBass has some good free beginner videos. There's no real need for UBass specific tutorials, but there are a few channels on YouTube to check out.
Stephen Cox comes to mind, and he has some good UBass specific content such as comparisons of the different string types on essentially the same instrument.