What Am I Allowed to Do at a Mock Seder?

Responsa Radio #102

My family are coming in from 1000s of miles away for the eclipse on April 8th, but they won't be around for Pesah on April 22nd. I want to do a mock or model Seder with them, but I know some things are only supposed to be done on actual Seder night. What should I include or exclude? How can I make the mock Seder feel substantive, but at the same time, still a rehearsal and not a replacement of Seder itself?