1) The only E+ on a 145 is the exit row, 1A and the two seats on the bulkhead. I don't think you can have a lap kid on the exit row, so either you had the bulkhead or you were in a regular seat to start. There isn't much difference in the seats, a few inches of legroom. Much less difference than between E+ and E- on mainline flights.

2) UAX FAs tend to be crappy when it comes to customer service. A lot of them have the "respect my authority" attitude. Remember that they're not UA but Expressjet, or Skywest, or whatever employees. They get paid squat, and are many are either fairly new to being an FA or were laid off by the mainline airlines and are bitter. There are some good ones, but I've seen them be anal about small stuff that mainline FAs don't get worked up over.

As always with the seatbelt light, if you need to get up, I would get up. Go to the bathroom quickly, or get whatever you need out of the bin. It shouldn't take two long to get two kids' jackets out of a bin.