Given the current ring size of 5, does that mean anonymity is limited to 1 of those 5 accounts? Can a given withdrawal tx be traced to 1 of the 5 depositors?

Would increasing the ring size to 100 and disabling the ability to close the ring early increase anonymity?

If a depositor takes the first slot in a ring, could an attacker simply fill up the other slots, watch for a withdrawal event and therefore attribute it to the original depositor?