I find myself uncertain about how attack codes are written in PF. I come to this via examination of the benefits of hydrae as waxwork creatures. In 3.5, a hydra makes a pretty impressive zombie, because its "attack" line is an attack with all of its heads. This means it doesn't need a full attack to get all of its attacks. But in examining the hydra in PF, I realized that there are no "full attack" lines and that the hydra now has the Pounce special quality (which a waxwork version would lose).

What are the base rules for how many attacks monsters can use in a standard action? Are hydrae good waxwork creatures?

I think the loss of fast healing doesn't hurt much when they have the waxwork regeneration to compensate. Their "hydra heads" special quality remains, since adding 2 new heads when one is lost is a definite improvement to their melee attacks. "Hydra traits" is questionable, because while it does contain the rules that make heads individually targetable for removal, that by itself isn't an improvement to the melee attacks until linked to "hydra heads." I'd probably house-rule it in place just because it's otherwise a lot harder to beat down a waxwork hydra, but...not sure if it's RAW that you could cut off a waxwork hydra's heads.