This is an explanation of season 3 so it's not so confusing. Obviously I don't have a clue what's happening in the real season 3 so it might not make complete sense but I tried lol :)

Ash and Mackenzie escape death as Faye shot the police. The police checked Ash and Mackenzie and thought they were dead. They then took Faye and Fez to jail and Marie (fez's grandma) to hospital where she was kept a watch on. Ash and Mackenzie had to escape before anyone came back to like check the scene or whatever. There was a mix up with the detectives and people who were supposed to take Ash and Mackenzies bodies to the Morgue. It was the hospital guys first day and he thought that we was only taking Marie to hospital and Custer to the morgue and told the detectives he took the bodies. They never realised that Ash and Mackenzie had escaped. Ash and Mackenzie then went to a safe house Ash and Fez had and they stayed there to take cover until Fez got out of jail.

There was a teleport in time of 2 months. Fez was released from jail as he was seen un-guilty for the death of mouse and Custer. (I know it doesn't make complete sense but deal with it lol) Faye is still in jail as she killed the policemen.

Ash and Mackenzie found a way to contact Fez and tell him to come to the safe house. Fez didn't know it was them and just assumed it was rue or something. He arrived at safe house and saw them and they were all in tears.

-------rest of season

stayed on the down low and had to find ways to hide themselves as they were supposed to be dead but no one knew they were supposed to be dead besides the police that killed them, which had died in a shooting not long after fez was released.

They were allowed out now but still had to keep on the down low.

Fez bought an actual house and they started dealing again. etc