was firestar made aware of what willowpelt did when he was gone?
He was. When he got back, he was filled in on the entire situation, everything from Longtail's accidental blinding, the descision to continue the boar hunt, BloodClan's change of power, and Willowpelt's betrayal which caused Elderberry's unintended death.
He decided to uphold Graystripe's ruling and make the deputy change official, as they decided on Longtail's semi-retirement so he could have the space he needed to figure himself out. Willowpelt would remain exiled until further notice.
Willy re-joined the Clan sometime just before the destruction of TNP, after Rainwhisker and Sootfur became warriors. It was decided it was already a hard punishment to have missed such a large portion of her kittens' childhoods, after losing Whitestorm. She can't atone in exile.
After Cricketclaw's death while the destruction of the forest was underway, she started acting as Head of Hunting again. It was a really difficult time and a lot of cats were injured, starving, or dying. Her experience was neccesary.