what would happen if one of the presidential candidates died?

You have 4 viable candidate running. If one of them died and there wasn't time to replace them, the election would still take place.

The party would choose the replacement. Apparently Dems had that meeting just after 9/11 when Hillary seized up then fainted. Speculation is that Bernie would in fact be the guy.

They would replace them with a look a like hobo off the streets

I believe the last one left gets to be president or they restart the campaign.

He or she would be buried or cremated. And then the rest of us would move on, as the Clintons so charmingly put it.

Donald did not look well last night.

Ok