I'm doing my PhD in one of the schools that you listed.
- I was 30 when I entered the program.
- I did my UG from an uni. somewhere in the east. It has good reputation, but I don't think it is a "brand-name" sch.
- I didn't have a Master degree to show when I applied.
- I wasn't an RA for 3 professors (although I did some work with a prof for about a year being I applied).
- I was also involved in a start-up for a few years.
The only thing that I trump you is a higher GMAT - just a bit higher... around 70 points more... So I think you are in good shape.
Ok, I'm joking about the 70 points