That'll help you figure out what direction to aim in before speaking with a bank to figure out how much you can qualify for. 

As for the ATM business, that is exactly the plan- build it up for 5 years then sell for 7 figures.

One of my goals is to go through my past tax returns, and figure the ROI my rental properties with taking into account the tax savings (I typically calculate the ROI on net cashflow at the end of the year)I have a W2 so I generally aim to maximize my pre-tax accounts - 401k, HSA, IRA to a backdoor Roth IRA, 529My "losses" would be passed forward since I don't qualify as a RE professional nor have active RE losses.

I have plenty of capital to go any route, just trying to figure out the best path.

At the same time you're figuring that all out, get your brother and friend under a lease, or at least, a written agreement both parties can agree on.

@David LewisRecommend you first figure out the property Class you want to invest in, THEN figure out the corresponding location to invest in.Property Class will typically dictate the Class of tenant you get, which greatly IMPACTS rental income stability and property maintenance/damage by tenants.If you apply Class A assumptions to a Class B or C purchase, your expectations won’t be met and it may be a financial disaster.If you buy/renovate a property in Class D area to Class A standards, what quality of tenant will you get?

Recommend you first figure out the property Class you want to invest in, THEN figure out the corresponding location to invest in.Property Class will typically dictate the Class of tenant you get, which greatly IMPACTS rental income stability and property maintenance/damage by tenants.If you apply Class A assumptions to a Class B or C purchase, your expectations won’t be met and it may be a financial disaster.If you buy/renovate a property in Class D area to Class A standards, what quality of tenant will you get?

I figured if I was going to owe Capital Gains, a HELOC would make sense since you don't have to pay Capital Gains on debt service.

It had a mobile home park component, self storage, commercial and industrial tenants but it was interesting figuring out how all the numbers worked together.

A way to look at it could be to find buyers first and figure out their buy box and after that go out and hunt for deals for them and run it by them when you find something.