Oh, I realised I never posted an actual reply here.
I’d love to do a community collab, and was gonna make a post about it sooner or later. As for the date, I agree with what Zizzy said. I wasn’t very fond of the way derpibooru did it (given that you would do the 2020 collab in 2019; never felt logical to me), so a mid-year date works perfectly.
Plus, now that I’m an assistant, I’d gladly put some of my time into helping make it happen.