May I use one E2 investor Visa to purchase 2 different business?

You cannot have to E2 visas simultaneously, but you may invest into and manage two enterprises at the same time, if your petition is structured to...

Can I fix my wife papers if she came legally

First, you need to get a consultation with an immigration attorney. Coming legally does not necessarily mean eligibility for residence. Many issues...

Does an E-2 spouse need an EAD to work in the business of the E-2 visa holder?

Yes, a spouse of E2 needs a work authorization to accept any employment, including the one in a family business.

N-400

There was a temporary glitch in a system that affected some already filed petitions. You can go ahead and file if you qualify.

Unless there is some underlying issue that makes you worried, postponement in adjudication is not an alarming sign.

Where do I go to first ? How long is this process going to take? How much will it cost?

Seems like your mother had abandoned her resident status. If she has a qualifying relative in the US, a new petition may be submitted.

I do not see any issues with crossing a check point in your current status.

Publishing mobile apps to US app store and earning income as an non-immigrant

This activity may be construed as unauthorized employment.

Do I have to file I-130 again which was approved with denied I-485 five years ago?

You need to call USCIS to upgrade your I-130 case to the "spouse of US citizen" category. Most likely, you will be told that there is nothing you...

Everything filed concurrently may be submitted in the same package.