I didn't actually expect Fox to stick with the rules of excluding certain candidates. Shame, really.
I guess if one of (or several) the major candidates would refuse to participate in the debate unless everyone was included, they would have to allow it. I doubt any candidate would do that, however.
With all 17 likely candidates on stage though, you'd have to go for 3.5 hours. (3.5 hours works out to 12.3529 minutes per candidate, roughly the same as the planned 2 hour 10 candidate debate, which works out to 12 minutes exactly per candidate) And no one except political junkies would watch a 3.5 hour
debate.