Hello there, Jimbell. Welcome to planDisney!
If you have a valid 
Annual Pass and the day you are planning on going to EPCOT is 
not one of your 
blockout dates, you should be all set to join that 
Virtual Queue on a 
Good-to-Go day. Similarly, as long as your friends have date-based 
theme park tickets, they should be able to join as well! Just make sure you are all connected through the 
My Family & Friends list, that you confirm your Boarding Group before 7 a.m. through the 
My Disney Experience mobile app, and that you're refreshing the app right before it turns 7 a.m. so that you don't miss your chance!
Now, Jimbell. I'm going to say something crazy. And if you're like Hans from 
Frozen then 
you LOVE crazy. I'm sure you know that if you don't get a Boarding Group for 
Guardians of the Galaxy: Cosmic Rewind in the morning, you have the chance to try again at 1 p.m. as long as you're in 
EPCOT. But if you don't score a spot for Guardians in the morning and you want to pivot and try for 
TRON Lightcycle / Run Presented by Enterprise at 
Magic Kingdom Park instead, you technically could do that if you're going on a Good-to-Go day. You see, when you go on a day that 
requires a reservation, you can only try for a Virtual Queue spot in the morning for the attraction in the park at which you have the reservation. You can't really pivot. But on a day that 
doesn't require a reservation, you can go to whichever park has the attraction for which you score a Boarding Group. So if one doesn't work out, you can quickly try for the other (subject to availability).
Okay. So here's where we go 
completely crazy. And if you're like Anna, you like the 
really crazy things! Now, I will warn you that this isn't an easy maneuver. And it requires a bunch of luck and some hustling. If you get a Boarding Group for Guardians at 7 a.m. and you are called back and ride early in the morning, you can technically travel over to Magic Kingdom Park and as long as you are tapped into that park by 1 p.m., you can try for a spot in TRON's Virtual Queue! Once again, this does require some luck. After all, at this time, you can only be enrolled in one Virtual Queue at a time. So if you're in the Guardians queue and haven't ridden yet, you cannot try for TRON. But hey, it's good information to have in your back pocket. Oh, and if your friends wanted to do this with you, they'd just have to have the Park Hopper Option on their ticket!
Of course, I also understand having your heart set on EPCOT and/or not wanting to leave a lot up to fate and run around. EPCOT is always a solid day. Guardians or no Guardians!
If you have any other questions or want any other (crazy or not-so-crazy) ideas, 
feel free to reach out to me.
Finish each other's sandwiches,
Matt