Sorry for taking forever to get back to you on this, I was on vacation and then at a conference.
I highly support the community (you all) completely running RacketCon.
My opinion is that you don't want to do some complicated the first time, so either make it entirely online or entirely on-site and maybe stream it but don't stress about the remote audience. The Racket Management Team can coordinate use of the Racket treasury if necessary for getting a physical venue, but it is often cheaper to work with a university and get the space for free --- if that's the direction you want to go.
In my experience, the CfP approach does not result in enough talks and you need to explicitly solicit them from individuals and then shepherd them to the finish line. When I run it, people give me a bio, then title, then abstract, then draft of materials, then rehearsal (sometimes live, sometimes record), then we revise together. In the online style, they submit a final version; while in the on-site, they give the real presentation. I find that two to three weeks between each deadline works well and if you compute the min of that time (- conference-date (* 4 (weeks 3))), if the speaker has more time than that... they won't do any more work, so there's no point doing anything more than lining them up before then.
So, I'd say that you need roughly 2 to 3 months to make the talks happen, but you need more like 6 to 9 months to get a venue and work out all those details. So, now would be a good time to plan a live event in the Fall... you're not too late, but you should get started. If you'll do it virtual, you can put everything together for the Fall starting in July or August.
Jay