The 4 annual comp tickets are not subject to blackout dates -- you can use them just like a ticket you would purchase directly from Disney. You do need to make park reservations, though, at least through January 8th or 9th. (something like that.)
Mine have typically arrived at the end of June and into July and end of December into January. It can really be any time in those windows.
Main Entrance Passes and Guest Passes are subject to park reservation availability as well as blackout dates. And they will still require park reservations going forward, though I've heard something about "Good to Go" dates where you won't need reservations. Not quire sure how that will work. I'm still waiting to hear what I'm going to need to do for my January trip. The blackout calendar is only showing through the first week.
Another tip -- the Main Entrance Pass holder needs to enter with their guests. One time, my friends and I were staying at a Skyliner resort (all of us CMs who work out of at a Disney office out of state) and we were meeting up with a local friend who was using our guest passes. They were driving in from their home. We entered Epcot through the International Gateway and they entered through the main entrance. My friend whose pass was used got a written warning about not entering with her guest. It's now on her account, and if it happens again, she may get in more trouble. We had no idea it would be such a big deal. We likely should have had him meet us at the resort so he could take the Skyliner with us. Lesson learned.