All you need to do it download the GMr game file you are playing but rather than selecting hotseat you select mod, and after selecting your mods you have the option to load a save.

I have done it on occasion to use a mod that reduces bloat in save files. It takes an extra minute.

As for the amount, I used 3 at one time with no issues.

The AI continues his moves, but has the tendency to change all the production. move warriors and negotiate on their behalf. Essentially they play the turn.

The file might be too bloated to load, it is common issue if you don't close civ 5 after each game and reload it again. There is a mod to reduce the size, I can find the info if you think that might be the issue.

I usually put on the "kick on skip turn" equal to how many turns he has missed, then wait 5 mins and it should kick him and you can revert the skip turn back to what it was.

Best option is to revert the rurn.

They get taken over by the AI if the player is no longer present in the game.

I'm in, but on Vacation from my computer til mid-february.