If these are the choices you want to stick with sure.

A 3-4 unit requires you to meet the self sufficiency rule which can be difficult in higher cost areas where the mortgage will be high and rents won’t cover the mortgage at 75% of lease agreements.

That is your choice but I wouldn’t expect your current tenant to ever cut the grass.

Before you make a choice I would have a thorough understanding of the return metrics associated with all of the scenarios.

That is the hardest part for most.The way you find/get these leads will make or break you.What I will tell you next is not the most popular choice, and that is exactly WHY I am in such a great position.Get a website immediately.

If someone is looking for a combination of good economic/demographic trends and good cash flow, Indianapolis and Kansas City are good choices.

So again:  You need discounted properties (marketing) + you need cash buyers.Pick your weapon of choice for finding discounted OF MARKET properties (I strongly suggest FBads PPC DMM and SEO), and while that is on going start posting EVERYWHERE that you have or will have a ton of offmarket properties, and whom ever joins the list now will get first dips.

i'm looking into BRRRR strategy that in a certain way could speed up of portfolio growing. in case of No US citizen re-finance could be an issue or registered LLC in US with lawyer with power attorney could be sufficient to have money from bank? 

Having sufficient death benefit that pays out no matter when you die ensures your obligations *as well as* your various savings accounts (retirement, college savings, etc) "self-complete." 

Ultimately it's your choice.