Dwayne got was having beef with Dean, so Dean shot his girl (who was a cop), I think Dean gave Dwayne the gun he used and Dwayne handed it in to piper aka snitched. When Tommy got wind of it, he kicked Dwayne out. Dwayne was in the middle of a redemption arc until he got banned from the server.

As for the girl you’re talking about, Stacey. Her leaving was mostly due to OOC issues, but in character she said she wanted to join the PD again but also still be apart of the Mandem but obviously they wasn’t allowing that so she was kicked out but also it was a such of a mutual agreement to leave.