You will have two important dates. Your hire date is the day that you begin indoctrination, and this drives your pay (annual pay increases on this date). Your class date is the day you begin training and as mentioned this drives your seniority number.

On or before the first day of indoctrination they will give you a list of available bases, planes, and training dates. Can't speak to LUS options, but expect MIA, LAX, and LGA bases with Airbus and 737 options. Everybody in your indoc will be listed in order of age and the oldest picks first choice and so on down the line. You want the earliest training date in order to get the highest possible seniority number, even if it means a base you don't want (they're all so junior you should be able to switch -- I moved from LAX to MIA before I even started training).

I can't personally speak to the LAX commuter bases, but I haven't heard too many people have issues with them. I commute from DFW to MIA and aside from one major storm that wiped out an entire evening of flights, including my ride, I've never had a problem getting there. The key is making a plan early. I use the jumpseat system to ensure a ride, but I've only had to use it once or twice (if there's room in the cabin, they'll give you a seat). The one time weather crumped it for me, I called scheduling to explain that I had a seat, everything was cancelling, and they got me a positive space seat the next morning and adjust the start of my reserve time -- wasn't an issue.

Your summary is still very accurate. 737s were supposed to be moving to the same pre-study system as the AB to decrease ground training, but I don't know that they'll converted yet.