Apply H4-EAD with 6 months pending on visa

I just received my i140 and my visa expires in December. Now my attorney takes their own sweet time to file for the extension which can range from 1 - 2 months. My question is this - Can I file for my spouses H4-EAD without waiting for my employer to file for an extension. So these are the scenarios

  1. I file my spouses H4 EAD this week based on my current i140 and visa.
  2. I wait for my employer to file my extension(~2 months) and then also apply for my spouses h4 extension and also file h4ead with that.

In scenario 1, this is what I’m expecting - If I file the H4 EAD now, and if it gets approved before December, I would file for an EAD renewal based on the new extension that I would expect my employer to file within the next 2 months. My employer would be filing the extension in premium. My spouse can still work based on the new 180(or is it 540) days rule that USCIS has.

If the EAD doesn’t get approved before December(which is more likely), what would happen in this scenario? Will she get an EAD card sometime in January or Feb next year with a backdated expiry date?
I’m not really sure on what would happen.

Or would you suggest to wait another two months for my attorney to file my extension and then file my spouses extension and h4 EAD altogether?

Generally USCIS will send RFE to submit proof of valid status and you can respond with the newly approved copy of H1B amd H4 I-797.