What is the position regarding existing unprotected deposits ?

1) I have tenancies dating back to 2008 where the deposits were not protected. Providing I protect the deposits within the 30 day deadline (after 6 April) and give the tenants the prescribed information, does this remove the tenants right to make a claim against me ?

2) Will all the protection schemes (mydeposits, DPS, etc) accept the deposit within the 30 day period (even thought the tenancies started in 2008) and would there be additional penalties ?

3) One of my tenants hinted they may move out in the near future, however I do not have a definite date at present. Could I just refund the deposit to her before the 30 day deadline to avoid her making a claim against me ?