Of course these things are never certain, but I'd bet you could pull a top 10 admit with that profile, assuming your
LORs are very positive.
You've done enough RA work that the marginal benefit of another RA position is very low for admissions committees; however, the
LORs you get from these profs could certainly be very good. So basically, I would say if you think your current letters are lacking, do the RA, otherwise apply. Getting another letter from a well known economist might get you a marginally higher admit, but you gotta decide if thats worth 2 years.