How could the job creation be counted in a joint venture?

You should consult with an EB-5 practitioner. All we can tell you is that the EB-5 regulation says the following:

Commercial enterprise

means any for-profit activity formed for the ongoing conduct of lawful business including, but not limited to, a sole proprietorship, partnership (whether limited or general), holding company, joint venture, corporation, business trust, or other entity which may be publicly or privately owned. This definition includes a commercial enterprise consisting of a holding company and its wholly-owned subsidiaries, provided that each such subsidiary is engaged in a for-profit activity formed for the ongoing conduct of a lawful business. This definition shall not include a noncommercial activity such as owning and operating a personal residence.