Can I start the process of obtaining my Driver's License in California with my Employment Authorization Card and SSN?

Yes, you can apply for a Calif DL, but it will be limited to the expiration date of your EAD.

Can my husband be deported having the form I-797c?

And what does the form say: receipt, notice of approval, welcome letter? Depending on the type of notice and the circumstances of your case, this...

Here is to check the processing time for your local office (from date of filing, not biometrics.)...

Yes, this is all very confusing, and it is not at all obvious that your I-485 was eventually approved after the reopening of the case. You mention...

Can I get denied a i485 denied after approval of PiP?

You have very serious issues here. Making false statements in your PIP application (as seems to be the case here) won't look good. Your old...

No, you can't assume anything. Maybe the COS is approved, maybe not.

Do I need to wait a decision or any notice from USCIS after they received my documentation for RFE?

The delay is not unusual for a response to RFE. However, an RFE is generally a sure sign that the case needs attorney involvement.

Yes, you can use white paper. In the old days, I-130 was yellow,G-28 was blue, etc. That was pretty, but it is no longer required.

For EAD renewal

Agreed with Mr. Capriotti. Sadly, there is no need to calculate the exact 90 days any more.

Can I apply for another H4/H4 EAD while current H4/H4 EAD is in process?

Exactly. And it wouldn't be a bad idea to ask your attorney.