Developer question on strategy for resuming game with a lost remote client

[BroadcastGames]

I'm seeking recommendations/experience/advice on how to approach a client that resumes a game but has lost all it's previous data stanza (JSON 'update'). Is it enough for my server to just hold the last JSON "update", or can I request RemGlk to give me a 'total situation refresh' of all graphics/sound/timer/content lines to get to the 'current state'.

Also I'm pondering the case of multiple clients viewing the same player in multi-cast fashion. What would I send them in a "join the in-progress adventure" so that their representation of the story output is the same (obviously multiple client's should act on timer etc).

Thank you.