Case transfer does not mean a good or bad decision. It is their internal process.

How to get visa number after I-140 is approved?

This is a complex procedure. Please seek private advice.

Can I go from L1B to H4 visa status without leaving the US?

"yes" and "NO" in all probabilities.

Is filing Form I-130 and Affidavit of support necessary to get a nonimmigrant visa?

I-130 and affidavit of support are never required for nonimmigrant visa. You can benefit from contacting an attroeny.

Is it nessecary to file Form-I- 130 petition and financial support before interview if I apply for K-3 nonimmigrant visa?

You can benefit from retaining an attorney to apply for an appropriate visa.

Can I apply for naturalization?

it is always a better idea to check with an attorney for advice.

Health case

Unfortunately asylum under the health grounds you are describing is not a good idea.

I am a green card holder , I have been out of the country for 8 continuous years , can I reenter the country ?

it depends upon why were you away for this long. Some reasons are justifiable that you did not abandon your greencard most others are not.

Can I file for Conrad 30 waiver right away as my residency training starts?

You would want to wait and not be in such rush as suggested by other attorneys.

How long waiting it will take to issued work authorization after captured biometric?

around 90 days from the initial filing but processing times always change.