| Darkwolf117 |
Multiattack won't reduce any penalty here, because neither the bite nor the claws have a penalty. Natural attacks are categorized into primary and secondary, and only the secondary attacks get the -5. Bite and Claw attacks are primary. (You can check out the table in the Bestiary. Scrolling up a bit is where it discusses what primary and secondary means for natural attacks).
As Marthian said though, if the cat makes a full attack, they get all of their natural attacks. You'll be rolling once to hit for the bite, and once to hit with each claw (so three total), and they'll each do their damage as appropriate if they hit.