Can my son to come on visitors visa to me and my daughter's family?

He has to apply for visa , most of the time when I 130 petition is filed , its more likely that his application for visa will be denied .

If my deferred action application is approved can I travel inside the united stated with my EAD card

Yes.

Co-sponsoring relative's affidavit of support if my wife is still obligated to support me

Please clarify your question, are you signing a sponsorship for your relative ?

Can I get my passport stamped while waiting for receipt for form I751.

Yes you can try.

Anyone with Experience Processing an E-2 at the Consulate in Madrid Spain?

There is a standard procedure for E-2 requriments , you have to provide source of investment contracts and all supporting documents.

I received stamp signature on I 20 from DSO but the embassy in Japan said they need to confirm with Washington. What do I hear?

It sometimes depends on the type of school; some school officials put a stamp signature and others only sign.

Do we need to transfer pending asylum case when we move to different state?

You have to transfer your asylum case to the state of your residency.

I would like to know what I should do about my immigration case I-360 which was denied based on the VAWA?

Contact an Immigration attorney as soon as possible who can assist you.

I try to file my i 485, but I do not have birth certificate

You need birth certificate and passport.

You have to leave United States upon expiration of your I 94 card, you have an option to extend I 94 up to six month.