First timer to Zihua - A couple of questions

Hi,
We're flying into ZIH for our first stay in Zihua and would appreciate guidance on a couple of questions.
1) I've been reading some horror stories about going through customs. We usually have some snacks for the trip (chips, nuts, candies), is that going to cause any problems? What about my wife bringing in a CPAP?
Do I need to declare things like my iPad?

2) I'd really like to bring home some roasted coffee from a local producer. Any recommendations?
Thanks,