I've played for going on 4 years, took about a year long break and need some refreshers <3

what item do i use to reveal traits on hatchlings / carried traits on adults

you'd need a genetic testing kit, you start with a few 1-use testing kits and sometimes people sell them on the broker.
you can also buy a reusable Exceptional Genetic Test Kit from the diamond store, but a cheaper alternative is to just ask someone to test your pets for you. a couple of people advertise in the Groups, Guilds, Clubs, and Services but you can also just ask in the chat. ^^