H-1B extension and H4-EAD filing

[karthikjay88]

Hi all,

This is my current scenario.

Current H1B expiration - 26th August 2018
New H1B - Just started the documentation - Company does not do premium processing but I can. 
I-140 - Not yet filed. Expected to be filed in a month.
Wife visa status - H4

With the current issues surrounding H4-EAD, I am thinking to do as follows:

1. Do I-140 in premium processing. This is because my PERM processing took ~9 months and I don't want to take chance with my I-140 application.
2. Pay for H-1B premium processing (so that I will get my extension in < a month). Also, my wife will get her H4 extended.
3. File for H4-EAD once I get my extension and I-140 approved so that the validity of her H4-EAD will be more than a year ! ( I don't have any clue about the validity). 

Is this a viable plan or am I missing something here ?