You can't choose multiple creature types, such as "Cat Warrior." A Cat Warrior is both a Cat and a Warrior. It's affected by anything that affects either type and unaffected by things that affect non-Cat or non-Warrior creatures.

Once Kindred Dominance begins to resolve, no players may take other actions until it's done. Notably, players can't try to save their creatures after you've chosen a creature type.

You must choose an existing creature type, such as Vampire or Cat. Card types such as "artifact" can't be chosen.