I found that someone said that their cupcakes in a jar "lasts up to 10 days without refrigeration or can be frozen for up to 6 months.”

You are probably referring to "Wicked Good Cupcakes" which has that statement on their website.    Nobody but that specific company knows what type of ingredients they use or how they package their baked goods.  I imagine they have done some due diligence in order to sell the products nationwide, but who knows?   

Everybody's recipes and prep for cupcakes in a jar are going to be different.  I'd suggest you bake up a bunch and try them in 10 days.   Frozen?  Heck, yeah, they're going to be fine for six months. 

If you look at the FAQ's on the Wicked Good cupcakes site, you'll see they actually advise LESS time than they do on the Home Page. 

Personally, I'd say most stuff should be fine, but I'd be very careful about anything with REAL cream cheese!!!