To answer your second question, M1 postseason is very different from M2 & M3.
First, there are no regional tournaments. The top 20 teams make Nationals, with 4 play in games (13 vs 20, 14 vs 19, etc.) and then a 16 team single elimination tournament. This was amended from the 16 team tournament that was in place for quite a few years.
Second, any auto bids go to the Regular season champions for the individual leagues. Playoff tournaments for the leagues do not award bids. Any auto bids displace the lowest ranked teams, @Sheriff discussed this in his post on this thread from 13d ago.