I've never seen a formal debate like this, but I'm surprised this kind of stuff is encouraged. It seems kind of dumb to me. If they're just making stuff up, can't you just make stuff up back?
"Oh actually it's not Jesus but Satan that's returning to Earth...."
I imagine, beyond the novelty, this would be an incredibly boring debate to watch.
They have quotes from experts researched they can read off, which you can't provide a direct counter to (for 'oh it's actually Satan') because you have no experts you can rattle off, at least not without completely bullshitting. Coming up with an out of left field argument to surprise and leave someone without a good means to address the argument is extremely common both in L-D debate and the modern media yelling clown show that passes for 'debate' on news channels today.
"Oh actually it's not Jesus but Satan that's returning to Earth...."
I imagine, beyond the novelty, this would be an incredibly boring debate to watch.