For the first, I think the Resend button can already bundle all state updates to the recipient sleepy laptop. The calendar app itself already supports exporting & importing to JSON, so you may as well have that file in your Saved Messages before you leave.
For the second, I think client side plugins would also cover this, where a “docked” webxdc could have access to API to iterate through multiple chats, read and write messages there, wexdc state or more ideally communicate with other webxdc over some restricted API. Or as an MVP, be able to click on its buttons and read back its labels?