I've updated the Offensive Formation pages and Defensive Formation pages with some page help that hopefully adds a little more clarity to what you are looking at.
For defensive formations, you can now set LBs to Line or Cover. If set to Line, they will always be active at the line for that play. If set to Cover, they will not be active at the line unless they are selected to blitz. I also broke up the line and cover activities to hopefully do a better job of displaying what each player is doing in each formation set. Keep in mind that these are used to build your playbooks, so if you want a 3-4 sending 2 LBs in some situations and a 3-4 sending 1 LB in other situations, you need to make 2 different 3-4 formation sets. Then of course you can use them in the playbooks and still set the option to blitz which now always means send one additional player than the formation set is normally set up for. It is up to you to make sure you keep those formations straight and I will be working on ways to display your different formation settings when you are setting up your playbooks so you don't have to rely on crazy naming schemes.
I'm still working on passing logic so nothing new to look at with game results.