Normally, unless there are specific building code restrictions, the amount of units allowed on a lot is determined by the Floor Area Ratio. 

In general, if there's nothing in zoning or the deed restrictions prohibiting the division of the property, it's mostly just getting it resurveyed and presenting the new subdivisions to the local government (county usually) to have each lot recorded as separate parcels.

You could be a private investor for a house flipper, but then you would be the bank and I am not sure how that would sit with your faith.I would park the money in index funds if you can't do syndications just because you are restricting the possible use of your money in real estate.

While residential development is generally restricted in these areas, there are specific circumstances under which it may be permitted:Special Mixed-Use Districts (MX): In certain M1-2 zones, residential use is allowed when paired with a residential district under the MX designation.

There is an Hoa that requires minimum 6 month leases but that was only restriction.

Many cities don't allow drilling in the city limits, or have restrictions, but outside city limits and especially outside the metropolitan areas, there are fewer restrictions on drilling sites.

I was also told it was a business decision not a regulatory restriction.

Otherwise many many many agents spend a lot of time and effort finding property and writing contracts only to find that the funds can't be transferred, or they don't have immediate access to the funds, or they need some kind of approval from 3-4-5th parties, or there are exchange restrictions, or 9000 other excuses.You probably need to find them a commercial broker who can handle whatever kind of investment they want to make. 

We could probably push it to 70k income, but we take all of the good holidays for ourselves, and we have occupancy restrictions to lessen wear and tear on the property.

Using a Self-Directed IRA (SDIRA) allows pre-tax dollars to grow tax-deferred in real estate, but limits flexibility due to IRS rules and potential UBIT on leveraged properties.Investing through a Roth IRA offers tax-free growth and no RMDs, but funding limits and restrictions apply.