JJ2020: Yirei Shamayim who use Beis Din rather than violating the issur chamur of arkaos use the halachicly prescribed marital assets distribution in a divorce rather than the contemporary gentile law of 50/50.
There’s absolutely no halachic or even hashkafic problem with marrying a first cousin in any frum Jewish community, including the ones where it isn’t common. Marrying a niece is specifically 100% okay even though the “besserer mentchen” these days hold their nose when they hear that. Marrying a first cousin is actually recommended and encouraged by Chazal. See Yevamos 62b. And Hashem told Moshe Rabbenu to tell the daughters of Tslophkhod to marry their cousins (Bamidbar 36: 5-13), and the Torah says “tov” about it.