If President Trump said no to this debate then the media would spin that so that he was afraid of debating Biden, hilarious I know to think he'd be afraid of Biden but they would spin it that way. The dice they play with is loaded, President Trump knows that.
The Comrade Moderator can ask whatever the party wants;
"Trump you scum, why did you murder 220,000 people?"
"Thanks Kristen. When Joe Biden took a junket to China and took his son along, that violated all kinds of protocols and sure looks like open corrupti---bzzd" (Offstage , we cut off his mic)
"Uncle Joe, I've admired you all my life. Which do you like better, puppies or kittens?"
"Well Jill"
"It's Kristen"
"Oh yeah, well Nancy puppies are cute and so are cockroaches which are black children"
"Mr. Vice president, will you condemn that Evil pig Rump for killing puppies and kittens and eating them alive."
"When I was in the Vietnam war I had to eat rats to survive."
"Mr. Vice president, what would you say to all the families where there is an empty chair because Donald Trump MURDERED their families - we've cut your mic off Trump, so don't even try to respond"
"uh Jill, I just want some ice cream"
"Uncle Joe, the murdering scum Trump claims that these non-partisan debates are unfair and rigged, will you call him a ******* liar?"