Normally (prior to the Corona age) the annual expected return was over 10% (net) and the average appreciation around 6% annually.Taking into consideration that the time to complete a project is between 1-3 years (depends on the size) and my strategy at the moment is to develop the project and to cash out, I am not sure that offering a preferred investment is possible unless I am using my own capital to finance interest distribution.Actually, I am exploring 1.

My dad is retired and doesn't technically have income, and we couldn't combine my income with his credit score to purchase the property.

If you have the capital you're alluding to, around $150K, there's better routes to take than SFH BRRRR and depends on hold periods.

I had never thought of refinancing it with another lender This will depend on what your overall exit strategy is, also I would make sure you have several options in case the land stops appreciating.

This depends on the seller using your payments to make their payments. 

Something to keep in mind however is that your choices may be limited depending on weather your PMC filed for eviction as 'them vs. tenant' (which is quite likely how it is now), if so, then you will have two choices: 1) You will have to let them handle eviction until the end OR 2) you will have to re-file for evition as 'you vs. tenant'. 

Credit Score: A minimum credit score of 620 is generally needed for financing a rental Debt-to-Income Ratio (DTI): Lenders will look at your DTI to ensure you can manage the mortgage payments alongside your existing debt.

Articles of Organization (depending on the entity you choose), Statement of Authority, Operating Agreement (can be optional), Employer Identification Number (EIN).

There are a lot of variable depending on how you intend on operating your business and I would recommend hiring an attorney in the state in which you will be operating your businsess.

U want your parents to talk to their CPA FIRST.. if they go the development route they are now ( depending on the amount of units) creating inventory.. which will be taxed at ordinary income rates ( very HIGH)if they just sell they can 1031  and move on to something else.. many times when you run the math consider the risks of a partnership.. the sale of the land is far better than thinking your going to make some profit..