Resources for an on-line Seder
In the case of a single person or pair of relatives who cannot make the seder (e.g., grandparents, college-age student), incorporating the distant person via Zoom or Skype just might work, particularly if the family can broadcast their link through an LCD TV screen (biggest is best) and pass a microphone as necessary for optimal acoustics. This format may work with even two persons on separate feeds.
[Unless it is relatively brief—or targeted to a specific time during the Seder—a multi-screen seder experience may not prove successful.]
This article, "How to Host a Virtual Passover Seder," also includes excellent suggestions. https://www.heyalma.com/how-to-host-a-virtual-passover-seder/