franchising question

so each league will have its own city: LA, Berlin, Seoul
and the players will have to move away from their homes
who covers the costs?
for example, are the players themselves paying the rent for their new homes or will riot/org help them?

the orgs will pay for it - don't worry about player career stability as franchising makes sure all players and staff will be well compensated. Riot will also make sure all franchised orgs stay afloat - at least, unless the org fucks up immensely.

AFAIK Riot pays for all Riot staff - so casters, observers, etc.
But the orgs will be responsible for their players I believe.

everything is covered by riot games, and if I'm not mistaken, even the costs of the casters will be covered by riot games

That's why orgs get paid by Riot. And they have hard financial criteria to get selected