lf an Event is drawn which is discarded because it is a lower number than the one already in play do you still replemish the counters for Starbursts.

Official FAQ and Errata v2.2, February 05, 2008

Event Cards
Q: When you draw an Event card, do you always replenish
adventure counters or do you only replenish if the Event card is put into play?

A: You replenish adventure counters whenever an Event card is drawn due to a Hero attempting an adventure counter, regardless of whether or not the Event card is put into play.