H-1B 2016 Selected in Lottery: Stem Extension Pending and Travel to India in August

[pacific]

Hello, 

I have completed my MS in 2014 and got picked up in H-1B 2016 lottery. Since my OPT was expiring in mid June, I applied for Stem extension which is pending for 45 days. 

So my question is would I be granted Cap Gap till Sept 30 and Stem application would be revoked. Or I would be given new EAD for stem extension but my H-1B would supersede it on Oct 1. 

Actually, I have my sister's marriage in August first week and was curious of possible ways to travel. I know travel on cap gap is "No No" if you want to return on F-1 status. Since I can't take 2 months off, getting H-1B stamped is not an option either. 

Thanks