>>I have a list of events that I plan to attend while I am in the US,
>>which includes events July-October. I haven't purchased tickets yet,
>>but I could do.
It is possible that if you file for the extension the day your 6 months
expires, that you will have enough time to stay until October, since
when you file for an extension, you are permitted to stay until a
decision has been made.
For what it's worth, I don't think you have a valid (per UCSIS) reason
to stay in the US for 10 months. If there are events you want to attend
between July and October, then you could leave well before your I-94
expires, and return in July.