My bacehlor party - DCA to LAS

My flight departs at 6:05 am on11 May (flight UA1560, ) --> UA1524 from IAH to LAS.

Two questions:

(1) My flight at IAH arrives at 8:35 and the connecting flight to LAS departs at 8:55. What are the chances I'll miss the flight? Any suggestions?

(2) Any chances of getting an upgrade by explaining that I'm on my way to my bachelor party? I know it's a long shot but I figured if there's any way I can get upgraded, that would be great.

I only have frequent flyer miles with BA / AA so I cannot use those miles.

Is there a discounted upgrade that will be made available 24 hours before the flight, when one can check in?

Thanks all!