The "Gameday" export (as opposed to the mid-week export) is/can be used for gameplans and active/inactive players, right?

Ya, the pre midweek file kinda helps to see what your up against when you look at the other team

Yes, the mid-week export is optional and only exists on the schedule in order to prevent the AI from messing with your depth chart/game plan. Generally you make roster changes (signing free agents, etc.) during the mid-week export because these are the sorts of things that cause the AI to rearrange your depth chart if you played a game immediately.

The gameday export is meant to be the one where you set your gameplans and active/inactive players. However, you can use the mid-week export for this purpose as well. It's really up to you.

Groovy. Now I have several more days to perfect my Evil Gameplan of Domination!!!! BWAHAHAHAHAHAH!!!