So I can't speak to the LDS history side of this, but I can speak to the Jewish side of this. Many of these don't come from Judaism exactly--they're shared with Judaism, but they're just things in the bible. Presumably Joseph Smith got them there, rather than from Judaism. While it's possible that Joseph Smith met Jews in his life (even though the Jewish population in the US in the early 19th century wasn't terribly large, the population tended to not be so clustered, so he probably would've run into a Jewish peddler or shopkeeper at some point, even if they were only 1 of a dozen Jews in that town), there's nothing to suggest he had the prolonged interactions with a Jewish community that'd give him insight into Jewish practice.

That's true of several of these, but not all. The 10% tithe exists in Judaism, but it's much easier to find reference to if you read the bible than if you hang out with Jews for a while. I don't know enough about the LDS Doctrine of Service to say much on that. The bit on lay ministry and Jews being a "kingdom of priests" gets a lot more play in the bible than in later Jewish theology. I imagine this is true of Kashrut and the Word of Wisdom, though I don't know enough about Mormon dietary practices to be able to observe any links to Judaism that aren't just inspired by the bible. And I wouldn't say that Judaism believes in continuous revelation either exactly--there's some wisps of things like that, but not in the sense of actually having prophets around.

Wrt the 12 tribes--Judaism does have a thing where disparate Jewish (or non-Jewish) populations are linked with one tribe or another. But Christians have also been interested in these sorts of theories. I think it's more likely that Joseph Smith would've been able to get his hands on material in English from Christians rather than Jews on the subject. However, on this there was some Jewish-Christian exchange of theories, so it's possible if you traced it back for who read who you'd get to someone Jewish (quite possibly Menashe Ben Israel, a Jewish writer who was popular among Christians, and in England in particular).

For tzniyut--this is a bit different. The concept of some sort of dress code, particularly when praying, has a long precedent in Jewish texts. At the end of the day, though, Jews generally covered basically what their non-Jewish neighbors did. Until quite recently there wasn't a Jewish subculture around this--this is what people think of with "tzniyut". What it sounds like you're talking about, though, is Jews dressing differently, which isn't really part of what's termed "tzniyut". It's possible here that Joseph Smith was inspired by Jewish men who wear a fringed garment under their shirts. Otherwise, the Jewish community in the US probably didn't dress significantly differently from their non-Jewish neighbors. And many Jewish men in the US at the time probably didn't wear one at all, so I'm not sure how easily Joseph Smith would've known about it to have been inspired by it. I think a more likely inspiration are the high priest's underwear (which probably were white linen boxer shorts, basically).