So, I think that regardless of this meeting, there are already discussions in the community and among miners about the best way to mine the BTC without impacting the environment. The price of BTC can be impacted at any time, if there is this warning that on the 21st there will be this discussion, maybe people are waiting for what will be resolved and agreed between the parties for BTC mining and thus attract more buyers causing the price climb. I think drop won't go anymore just because the community is already aware of the BTC situation. And there probably won't be an increase specifically because of this meeting, unless something big happens.
Definitely yes, there are discussions going on already, but I don't think Elon Musk will appear at that meeting without a plan in his pockets. Not that he has a fully developed plan, but I can imagine he will have some ideas that at least he could make possible. I guess his companies will play a role and Dorsey could become one of the financiers of those potential endeavors.