What after CAP GAP?

The cap gap is extended by your school until CIS makes a final decision on your H-1. I assume your immigration attorney knows this.

Can I decide to change my mind and change visa from F2 to F1 by travel while my I-539 is pending?

You can certainly file for a visa at the US consulate. When you leave the US, the I-539 is automatically terminated.

The E-2 depends on your country of citizenship and last residence, as well as how you plan to start or purchase a business with $200k or so.

Applied for my under 21 unmarried child, priorty date is july 2017, i will not be neutrilzed before his 21 age, what about cspa

The CSPA has nothing to do with this. As long as he entered the US legally the last time he entered, and you become a US citizen before he turns...

About the new edit for immigration system will it effect the old case ( i-130 son over 21 for green card holder)

The President has nothing to do with this. More importantly, it does not matter how fast the I-130 is approved you still must wait around 8 years...

As long as you had valid work authorization, the change of names can simply be explained in the cover letter.

Visa Stamping?

Doesn't your immigration attorney know this? The prior visa is still valid for the new company. Also, the "company lawyer" is also legally and...

This has already been asked and answered. You are missing part of the case. In order to change jobs/employers, the I-140 must be approved AND the...

Since you are a US citizen, they must each apply on their own for an immigrant visa.

I-140 approved. Confused

If you are in the US you need to file for Adjustment of Status, not consular processing. You have an attorney so use him or her.