Will I have any issues applying for an H-4 visa with an approved I-526?

It should not be a problem. You are joining your spouse on a non-immigrant visa. Advisably, consult your EB-5 attorney to ensure proper planning is put in place.

No, the H-4 is dual-intent visa.

It is possible to do that since H-4 is dependent on H-1B which is a dual intent visa. Plan with your immigration attorney.

No. You will not have any issues applying for an H-4 Non-Immigrant Visa, even if you have an approved I-526 petition, after you are married to an H-1B visa holder. You do not have to prove nonimmigrant intent. Once in the U.S., and a visa number is available, you would be eligible for Adjustment of Status, along with your wife.

While you can, it may be faster to maintain the process of the case, since the case is at the NVC stage.

No issue doing that at all. This is because H visas are dual-intent visas. As such, you can apply for an H-4 visa with an approved I-526 application. However, assuming you are eligible to do so, once you decide to file for adjustment of status under your approved I-526 and obtain your conditional green card, you are no longer eligible or need to hold on to your H-4 visa.

H visa status is a "dual-intent" status, which means you can maintain H-1B/H-4 non-immigrant status in the U.S. while simultaneously processing for permanent residency/immigrant processing.

In theory you could do that, but there could be all kinds of problems doing this.

Probably not.

A consular officer may be a little more willing to deny a non-immigrant visa with an I-526 approved. They have so much power to deny visa applications for so many reasons.