Divisionals are the top swimmers from your division. I believe top 2 from each event. All stars- based on this list,
http://www.mcsl.org/AllStars.aspx
It’s the top 16 for each event in the entire MCSL league (92idh teams). Granted, many 13+ will scratch as there are club swimmers that have national meets that week. Also, some swimmers are top 16 for almost every event. They can only swim two events, and will need to scratch the others.
All star relays is the last Saturday of the month, individual all stars is the following Sunday.