What are the restrictions on a G4 visa holder to apply for EB-5?

There are no restrictions on a G-4 visa holder applying for EB-5; also, keep in mind that the new rule that becomes effective 11/21/2019 requires a $900,000 minimum investment (and placed new requirements and restrictions on TEA designations), so if you (and/or she) are planning on making an EB-5 investment under the existing rules, you should act quickly.

As a G-4 visa holder, there is no special set of conditions for EB-5. It simply requires two steps just like any non-immigrant living in the US. First, an I-526 will be filed and if it is approved the petitioner will subsequently proceed to the adjustment to immigrant visa by filing !-485. However, pay more attention to filing an approvable I-526 and meeting all the requirements for EB-5.

A G-4 can apply for an EB-5 but cannot work for the company. They can, however, invest and apply for a green card and, when approved, work for the company.

She is not authorized to work (including self-employment) under her visa, but it may be a passive EB-5 investor with a policy formulation role if you are work-authorized manager who will set up and manage the EB-5 commercial enterprise. Business documentation must be properly prepared for direct EB-5 case along with an EB-5-compliant, five-year comprehensive business plan. A G-4 visa holder is required to get a waiver of diplomatic rights, privileges and immunities to process for LPR status if I-526 petition is approved. Hire an experienced EB-5 immigration attorney to assist you.

I do not believe there are any restrictions on current G-4 visa holders. Just like everyone else, she needs to file the I-526 petition and, upon approval, proceed to adjustment of status to conditional permanent residency.

No restriction, only an added requirement to submit a waiver of diplomatic rights, privileges and immunities for processing for permanent residency.

They are not restrictions. The process requires certain steps of preparation to be taken by your attorney before you file for the change of status.

No restriction that I have ever heard of.

None. She can file an EB-5 petition on Form I-526, but is not authorized to work until obtaining conditional lawful permanent residency.