When should I make my "smores" wedding favors?

If your wedding is on a Monday I would do it Friday or Saturday. Maybe you can ask your FH to help to make it faster.

What are you putting them in? If it's something that seals up tight, you should be good about 2-3 days out.

Are people going to be eating these the night of the wedding over a fire pit, or is this something that they're taking home with them? Could you do everything individually wrapped and then let people take one of each in a little baggy?

If you're putting them in little plastic boxes like I've seen on Pinterest, you could then put the boxes inside of airtight Ziploc bags (buy big ones so you can fit multiple ones per bag) to keep them from getting stale. I doubt those boxes would be airtight.

It's for them to take home!

@Amy thank you so much for that idea! I love that! seems like the most practical thing since yeah, I am putting them in clear plastic favor boxes that definitely are not air tight. So If I do the ziplock thing I should be able to do it the weekend before (my wedding is on a Monday).