Hi! Newbie here and would like to get some advice from all the experts here...

I am MPC Green and recently called the MPC hotline to redeem round trip PEY tickets between HKG and SFO. Inbound is confirmed but outbound has to be waitlisted:

Outbound (all waitlisted):
2016 July 20 - CX 870
2016 July 21 - CX 870
2016 July 21 - CX 892

Inbound (confirmed):
2016 Nov 5 - CX 873

The waitlist expires on July 4th...so my question would be...:
1) any chance I can extend the waitlist deadline to a closer to departure date? Does that affect my order or priority on the waitlist?
2) if the outbound is not cleared, I can decide whether I want to redeem and issue the single ticket inbound right?
3) does anyone know if the chance of clearing this waitlist is high or not...or anywhere I can check the chance of redemption?

Thanks in advance!!