Possibly not allowed, but if it can be managed with temperatures, selling cookie dough to bake at home might be popular. I've done it as gifts a few times and it's always been very well received. People like being able to just pop something in the oven when they need a treat, but with varieties you can't normally find in commercially available dough. Probably not something you want to work out for this time, but in case anyone reads this thread later and is looking for ideas. 
As a presentation thing, especially as you have some unique flavors, what about making up little cards or pieces of paper that you can package with the jars with recipe suggestions for using the jams and marmalades? Maybe a simple bread recipe that makes good toast, and then other suggestions that would work well, like baked Brie or easy appetizers or sandwiches - just help people think outside the box for using your product. The kids can probably help with that and it will help them think of the marketing aspect of selling.
(I mean, you can double your sale if someone comes for a jar as a gift and you convince them to get a second jar for themselves to have on hand for a quick fancy snack for guests like small toasts plus soft cheese plus a dollop of quince or similar. I think people are more likely to buy fancy stuff for guests than for themselves a lot of the time. Oh, or maybe something would work well in a cookie, like thumbprints? I made a lovely chocolate cookie once that used a basic chocolate thumbprint dough, topped with some fancy cherry preserves from a farmer's market, and then a dab of ganache on top. Easy to make but not at all the 'normal' thing because of the preserves.)
