How can I use my EB-5 business for an E-2 application?

If the company is majority-owned by Canadians including yourself, this may still be an option provided you can show adequate intent to satisfy the consulate in Toronto you will not stay at the end of your investment.

If you wish to apply for a change of status from H-1b to E-2, you should consult with an experienced immigration attorney to confirm that you meet all of the E-2 requirements. Not every EB-5 case will qualify for E-2, but it seems like your case could potentially qualify as long as you own at least 50% of the business. Also, keep in mind that while the E-2 likely will not affect your pending EB-5, it is possible that USCIS or a U.S. consular officer in Canada may question your intention to remain a nonimmigrant and not abandon your residence abroad since you have indicated immigrant intention by submitting an immigrant petition (I-526). Again, an experienced immigration attorney should be able to advise on the required intent to qualify for E-2.

Changing status might be more likely than getting a new visa. I do not think the EB-5 would be affected at all, but it is the ability to even get the E-2 that may be a challenge.

No, this is doable.

Yes, you can if you are the majority owner of the EB-5 business. E-2 requires that you be the majority owner, among other requirements, of the E-2 enterprise.

Filing an E-2 would have no negative impact on your pending EB-5, assuming the consistency of info, of course. An issue here is immigrant intent. Consult with an attorney for proper advice.

Since the U.S. consulates in Canada are not open for routine applications, you could file a petition seeking a change of status from H-1B to E-2 by submitting evidence of your substantial investment in an active commercial enterprise that is creating jobs for U.S. workers.