Thank you for this very helpful response.
I plan on pursuing the IR/CP route, so quant skills will be required. I agree with your view that Coursera or other MOOC courses will not carry weight similar to a traditional class with a letter grade. My intent in pursuing these classes would be to signal to AdCom that I am cognizant of the math component in a PhD program and that I tried to bring myself up to speed. I already know Python - wish it was used more heavily. It actually is quite a fun language. I thought about R as well, but given very limited time on my end, I want to maximize endeavors that would increase admissions chances.
I graduate UG a decade ago, so LORs will definitely be a bit challenging. Noted on your other points of advice.
Thanks again for your post.