broadway flea 2018

So this year I am going to the broadway flea market for the first time! I am super excited but I have a couple questions.

I was wondering when they announce which actors are coming for autographs and which are coming for meet and greets?

I was also wondering if any shows still have a show that evening or if no shows have a show because of the flea market?

Lastly, I was wondering what time flea ends at?

They will announce in September which actors will do the autograph and photo lines.

And shows still have their matinees or evening shows that night

thank you! do you know if its announced early in september or right before the event?