For the kind of fingerboard wood, better ask in the Setup and Repair forum.
It might depend on the kind of strings. Roundwound or less polished strings can eat up the fingerboard over time (even a very small dent might result in a buzz).
Ebony is the best, I think, but better ask a luthier that has more experience with different woods.
The Stagg with the rosewood fingerboard is OK, but the body support is a bit weak. And it is a cheap Instrument, that needs some tweaking here and there. The curvature of the bridge is rather low.
Personally (coming from a DB background) I don't like the NS Design, even with an endpin (which is better than the tripod). Seems to be made for bass guitar players and doesn't feel like a DB. Less chance to change the fingerboard curvature than with the rosewood fingerboard Stagg. Also much more expensive than the Stagg (specially with the endpin and body support).
Since you played a bit of cello before, I think you might want an instrument that is closer to a real DB than to bass guitar (and that is bowable too).
I never had a Baby Bass in my hands, but the sustain might be short due to the pickup construction (that salsa sound, but less suitable for jazz), larger and heavier than the Stagg and the NS Design, and probably more expensive. Probably also closest to a real DB of these three instruments.
A real DB could be put into the corner of a room with the strings facing the wall. Could also be a "wrong" corner between the wall and something solid like a cabinet or a shelf. Then you can make a floor decoupler and f-hole stoppers made of foam (look at the british basschat.co.uk forum) and the acoustic bass is much quieter to your neighborhood. And then you got the real thing.
There is nothing wrong in using an EUB, but it not the best for learning DB, since it feel different.
And the solid body instruments are hard to hear for yourself if there is some noise from the streets. Remember that there is about the same vibrational energy going into the floor over the endpin than with an acoustic DB.
The only thing EUBs do better is flying with them in a plane (but even then you might need to unmount the neck from the body (usually no big deal) and pack it in a solid case. Real DBs that are made for travelling usually are very expensive (the chinese Christopher being an exception, but still costs some money with the case).
I have played a bit of cello, but want to make the jump from elec bass to upright... I'd love to get an acoustic, but I live in one room and there is truly no space for it (not to mention the rooms next door hearing the noise! 
