Query of B1/B2 visa holder for change of visa status(E2) presently in USA,

An initial E-2 must be applied for at a US Consulate abroad.

Substantial is very substantial ... more than $100,000 of funds from outside of the US. Meet with an attorney.

You can apply for an E-2 "status" from USCIS in the US, and if approved, will only be granted for 24 months. Good for while you remain in the US only. If you leave, you'll have to return with an E2 visa. The smarter thing to is to prepare the visa package, and once the investment is complete ("consummated"), apply for an E2 visa at the US consulate in your home country. You will the get a visa valid for up to 5 years (depending on your nationality) and UsCIS will admit you each time in 24 month increments. The investment must be "substantial" for the type of business you either create or buy into. There is no set minimum amount. For consulates oversea, however there is the minimum "psychological" threshold of at least $70,000 and with USCIS of at least $50,000. I have almost 20 years experience with having successfully filed E2 visa applications at consulates worldwide (was never denied) and stand ready and eager to help you. Call my office, even today.

From our experience, it is possible to change from B-2 to E-2. Yes, your dependents can come in on an E-2.