What is the best option COS with 245 (k) or H1b stamping and apply for COS?

First address this question to your attorney filing the I-485 as he is aware of all the facts of your case. If not convinced, seek a private...

Just for your mom

H1b and L1 approval together: Is status implicit or based on stamping ?

If both petitions are approved, go to the Consulate to apply for the visa based on which you wish to enter the U.S.

I am divorced and want to re-enter US and renew my green card

More information is required.

Can I join company without hasitation on receipt ?

Yes. If denied, you will leave the U.S.

Can a person have 2 statuses L1B & H1B for same firm and switch between them as required ?

It may work better if you seek L-1 extension so your spouse can work too. On H-4 he cannot work. The fall back is that on L-1B you will have...

Can me and my spouse apply for I 485 at different times.

Best to file together if possible

I applied for B2 visa extension. I have only 1 month left on my current I94. What happens if the result is delayed with a denial

If you stay beyond I-94 and the extension is denied, the visa is automatically voided.

I applied for green card through marriage with my 12 yrs old daughter . It was granted this past week with different expiration

Looks like an error. Both should get conditional residency for two years.

Question on Opt

You seem to be out of luck. There are no numbers for this fiscal year. For next year you could take benefit of cap gap if your OPT expires...