I have friends to visit tonight who bring a second PS4, can I somehow create a split screen to display a split image of the two PS4, for example, one at the top of the TV and the other below, possibly through a laptop?
TVs can't do that. Some monitors have this feature
The fact that a split screen of most monitors is not supported (ie 2 hdmi in and top and bottom is shown one) I assume that your monitor does not support this synonymous. Your friend would have to bring his own monitor.