help wanted with making custom entity

I made custom entity mod(with 1.18.2 snapshot), and I have 2point needed help.

1) custom mobs grow up and breed without problems. however, when the baby mob spawned by breeding, the baby have no owner. becuase I don't like this, I want to know how to change model of baby mob(NOT by separating them as different entity) or way setting their owner automatically.

2)If player do right click, the entity will open GUI.and I want display custom name of the entity which player clicked. but I don't know how.....

I don't know how coding fully.

BUT I know way edit and sample code.

+I'm bad at English,sorry