Won't this just make people stop working
and what if it does? Do we have a shortage of labor or a shortage of jobs?

In the economic sense we would especially during the transition period have less jobs available. With jobs being the way we get the money needed to survive (outside the welfare programs) the labor I'd assume would still be looking to work. Usually after some time a new method does come out that changes the paradigm, steemit for example. While it's not exactly paying all the bills as it stands right now, I'd say most people don't currently view time on here as 'work.'

The other side of this coin has less to do with the money and more on the 'too much time on peoples hands.' In many places really high unemployment mixed with lack of basic needs being met leads to more negative things like crime, violence, sometimes full out rebellion. Depending on the circumstances boredom can be a motivator to do both great and not-so-great things.

I rather like the citizenship share you mentioned. It reminds me of something I'd read (I Think Here) that got into business ownership in a similar sense. Whatever company you worked for, you were part owner. When you changed jobs you lost ownership there but gained it at the new place. It very much changed the sense of the group (however that's defined) towards a more cooperative view since everyone has direct benefit for the company/country doing better. Currently I don't believe this to be the case in most corporations or really for countries, for the majority of it's employees/citizens. Just cause you work hard doesn't mean it directly provides a benefit.

In some of the UBI experiments I've read, some of the people receiving UBI were offered a 'bonus' for doing certain things (usually community service, volunteering, etc.) but the voting/jury duty could easily fit in there. While conscription can be included, that one I'd have to think on some more...both because I'm always a little concerned on required military service (even though some places like Israel do have that in place for most if not all citizenry) it also takes up a larger portion of time to train properly, which also has it's own side effects. (not saying it's evil or anything, but a soldier can't be in a spot thinking how they feel about 'taking the shot' when in the thick of things, which can cause difficulty when back in civilian life.) It's all an interesting idea regardless!

This somewhat reminds me of Starship Troopers where being a citizen has to be earned in some way...military service was the main one mentioned in that book/movie. Things that are just handed to people aren't always held to be meaningful...to a degree this is why college fraternities require pledges to 'sacrifice.' Both because they want to establish the 'camaraderie' (I'm not saying frats are good, purely an example) as well as a decreased likelihood that they will exit the group easily since they 'know' the work, time and trouble that was invested.

I do think having 'shares' and receiving the 'trust fund' would be an interesting approach.

Have you seen the vivacoin project? It has some rings some loose similarities in my head to this.