As a former certified sailing instructor and frequent charter/weekender/racer and Coastie with a mix of newbie crew I would recommend covering safety until they can repeat it back. Nothing else really matters.

When I have been able to prep the crew in advance, I have found that calling it a sailing orientation cruise keeps it light and lowers expectations and anxiety.

After that, I give them an overview demonstration of what I'm doing and tell them that I will teach them as much or as little about boating/sailing/seamanship as they are desiring to learn, but there is no obligation to do so. They will learn best by doing.

That being said, my stink boat buddy and I had a 4 hour discussion on nothing but mainsail shape, trim and changing gears. The other sailing newbies left after the first 10 minutes.

Don't have a sail plan that counts on the newbies for anything and be prepared for you and your experienced crew to do or direct absolutely everything. Both of you should be on deck at all times while underway.

Let the newbies know that they are not being relied upon to do anything related to the sailing in order to remove some stress. If they do want to participate, talk them through it before, have them repeat it back, and then talk them through it during the action.

Just my .02