H4 question - H1B is expiring

my wife is on H1B and the H1B will expire in SEP/2015.

My wife want to take a break and will not work till the end of 2016.

A note here is that her I94- has a date till 2017

Now My questions are:

1.If she apply for H1B extention and can she be ideal with out working till 2016 with out paying taxes?

2.If she apply for H4 (because i am on H1B) after her H1B expires, will it be easy to apply again for H1B in 2016?

  1. What is the meaning of her I-94 is till 2017, is it any thing to do with not extending her H1B?