As I understand it, the Lyft vetting is more intense than Uber's. So many Lyft drivers can be Uber drivers, but the reverse may not be true. I could be wrong though, my only data points are talking with drivers and therefore anecdotal or hearsay.
I doubt it. My Lyft onboarding experience consisted of watching a couple of safety videos at an auto parts store instead of a 1:1 "mentor" session. Last I heard, mentors are gone in San Francisco.
Lyft requires newer cars, which could bar totally broke drivers.
I have perfect background check, of course.
Lyft is definitely hands-on when reacting to passenger complaints. They likely have sentiment analysis software for comments by passengers.
Lyft passengers are ruthless in ratings. It took me a while to recover from initial ratings while I was learning. At least your ratings are a rolling average of last 100 rides so you can fix the problem of bad ratings with new rides. Last week should help: got 17 5-Star ratings and no negatives.