Sorry to hear you weren't feeling well but I'm glad you're okay now! And no worries, I don't think anyone here would want to pressure ya and we still have plenty of time! Your health comes first!
Yes, the 700x700px at 600DPI will work fine for me! I'll probably do it the main file larger but send a version in at those specific specs.
I also have no preference on the upload time. I think it's a great idea to all post them at the same time and am fine with shooting for whatever time the majority deems they want. I'm not picky 
Also, I'm super excited to do this! This'll be my first collab! I'm gonna get started on the drawing ASAP so it's ready with plenty of time to spare! I like the idea of setting up a discord for it too. If we end up doing that my name is Kinley Pavone#7052 on there.