I have been looking on the help, forums, and blog for any explanation of what the tournament host is able to do to resolve problems caused by idle players. Does the host have the ability to force a player to join a game? Do other participants in the tournament also have this ability? How long before that option is enabled? Does the host have the ability to boot an idle player from a game that the host is not in? I did go and vote on some relevant suggestions on the feedback system...

No, I'm pretty certain that the host has no ability to force join or boot players in games which he is not involved in. Players involved in a game do have the ability to force join players after a certain amount of time, but I don't know what determines that time -- it may be tied to the boot times.

the host and anyone else in a specific game can force boot, which is the same timer as either the auto-boot or direct-boot timer. but the tournament creator cannot boot a player in any game that they are not in themselves

I guess this is why people have created and voted on a suggestion that this ability be added, in case both players in a give 1v1 match are idle...

In any event, I think it would be handy to have more explanation of this in the Help, or the blog.

Yes, the host can force join.

But he can not boot, once the game has started.

The solution is the autoboot option for tournaments that was just added. Fizz indicated that if you email him the stalled tournament he'd enable the automboot function to boot the staller and unlock it.