I ran a 4e game in person a little over a year ago. It is my wife's favorite edition, and she came to it after coming into the hobby with 5e, FWIW. I've looked into what's available on Roll20 for the system, and it's lacking compared to 5e (as you noted). There's a character sheet, which looks pretty serviceable, but you'll have to put in all your powers manually. I think it can be done. I would probably just do that for the PCs and then run the monsters off to the side in meat space. I wouldn't want to have to create every monster from scratch. I would just use the tokens and map from Roll20 but run the adventures off PDFs or physical books on my DM side.
If you'd like to test it out sometime before you present it to your group, I'd be happy to help you out, as a DM or player.
If you'd like to test it out sometime before you present it to your group, I'd be happy to help you out, as a DM or player.