A. 475

Grapples are the abomination of D&D!

A
Grapple actions are determined by BAB regardless of number of natural attacks.

(According to the FAQ you may only use one natural weapon to attack with while grappling.)

B
You can use the escape from grapple action in place of an attack, so based on the RAW alone you should be able to move away from the grapple and attack with all your natural weapons (all of them as secondary attacks) as a full round action.

The movement involved in the escape from grapple action is included so you do not need to take a move action or even a 5-foot step.

Grapple mentions nothing about leaving the involved prone.