gachaleiresamim

The Parshas Derachim is the go-to sefer for all this.

The Medrash says that Yosef kept SHabbos in Mitzrayim and his household showed the Shevatim that they did proper shechitah, and Ephraim learned Torah with Yaakov. They certainly kept the Torah in some form.

yekke2: why would Yosef and Dina be different? By Dina it says explicitly ???? ???? ??, which sounds like she was born alone, but it’s not muchrcah that she didn’t have a twin.