That's so sweet.Making mooncakes could be very difficult since there are many different kinds of them,like Guangdong style,Su style,Beijing style and so on.People in different areas have various tastes.So you'd better get that clear before you choose a recipe.

I thought the important part of giving mooncakes was to give away a box that looks expensive. 

It's a good idea though. I'd like to hear about the result of the project. 

Note: I sometimes have a bit of a problem with moonckaes, the main part is just a big blob of sweet stuff, which is great but quickly becomes a little nasty. Break the monotony by adding some nuts, peanuts, cashews, almonds, walnuts, whatever nuts you have handy. 

At one of the schools I was involved with they made mooncakes in the class. I remember them using some doughy white thing and rolling it up. Later eating it. I didn't want any because I knew who made it, but one thing was certain I didn't know who washed there hands or not. I ate one because the chinese teacher was urging me on to eat one. 

Do you have an oven? If you do then buy your favourite kind and warm them up in the oven just a bit and serve them ,claiming that you made them. Thats real Chinese cooking at its best.

Personally I think mooncakes are only good for hockey pucks.

In my opinion even if you make wonderful mooncakes they just won't have the same taste as something from the "hometown" so kinda lost before you've started.  Some foreign recipes are enjoyed here though - mexican can be for example.  A good Chilli or something, depending on what your in-laws like. That might work. Or just get them sh*t-faced first then anything will taste good