One big question is whether the devs want/need an internal UI library. If yes, make sure you speak to them a lot to know what they're after. If it's management

One big question is whether the devs want/need an internal UI library. If yes, make sure you speak to them a lot to know what they're after. If it's management thinking that the devs need such a library, or it would cut costs somewhere and the devs have not been consulted - then good luck.