Go here and read the OLL Flow chart
www.calguns.net
You will find more than enough info on converting your Ar over.
As far as the over 10 round magazines go, i am not 100% but it is not illegal to have them. you just cant buy them here unless you are LE. If you had them before the 2000 ban you are good to go. the part i am not 100% on is moving from out of state. You did legally own them and if you move to California, you technically legally owned them before you moved in.
Ask over on Calguns someone will know for sure.
Oh and DONT SELL YOUR GUNS, you'll miss them later.