How can I become a partner of an LLC as a tourist visa holder and later use it for EB-5?

If you entered on B-1, then you may set up a business such as an LLC, but you cannot manage the business. It should be properly structured with you to be at least in a policy formulation member role to qualify for EB-5. You may also receive distributions from profits. To qualify for EB-5, you must invest the requisite minimum investment amount originating from a lawful source of funds that will create the minimum required 10 full-time positions (at least 35 hours a week). Consult an experienced immigration attorney to competently prepare your case.

All the funds that you invest in the EB-5 business must be funds which you have obtained legally.

All your scenarios are possible. Advisably, consult an attorney who can help you in putting together the business plan detailing how you intend to operate the business so as to meet the EB-5 requirements.

I would want to help you set it all up the right way but I can see a lot of thing being possible.

You can be a partner on a B visa, although preferably if you had entered on an B-1 business visitor that would be much better. You can set up a business on a B-1 but you cannot work in it. The critical aspect for EB-5 is to be able to trace the source of your funds and then show how that investment will create 10 jobs.

If you do not have a work permit, you cannot operate a business located in the U.S. yourself. That said, you can certainly invest in the business as long as it is operated by your U.S. citizen business partner. Because you would be part owner of the business, you would certainly be entitled to collect profits from the business. If you intend to use the business for EB-5 application purposes as well, it is best to hire a professional to advise you on how to make the business EB-5 compliant. At the minimum, you would need to create 10 full-time positions, invest $500,000 for TEA projects or $1 million for non-TEA projects. These numbers and the definition of what is TEA, and what it is not are expected to change after Nov. 21, 2019, when the new EB-5 regulations go into effect.

Yes, you can. But you cannot work in the business before you get permission from the immigration service. Yes, you can operate the business remotely from Mexico and get profits. If you want to use it for an EB-5 application in the future, no, there is nothing to be cautious about at this point. But the minimum investment for EB-5 goes up from $500,000 to $900,000 on Nov. 21.

Yes, this can work but it would need more discussion to work out the details. It may be a conflict with a tourist visa if you intend to immigrate through EB-5, so you may want to do an E-2 first.

Yes, you can be a partner and help operate the entity from Mexico and still use the same LLC as an EB-5-compliant investment entity, provided the investment otherwise meets all of the EB-5 requirements.

Probably, but since you are in the U.S. you should consult with a lawyer who handles immigrant investor visas.