Another angle that is different about commercial or industrial there are businesses tied to the properties.

Yeah I get that one difference with deed transferring or not. 

I see the importance of having a team to help you out, but I don't understand the portion about paying back the loan, how much I should have before investing, if there are anything different if I will be investing from another country as a citizen etc.

How long it takes to be financially ready is different for everyone.

The valuation and market value of a multi family property differs from a single family and you want someone that understands the distinctions if you go that route.

However, FHA rates will most likely be lower than conventional (but this can be a larger difference for different price ranges)Conventional mortgage insurance drops off automatically at 78% loan-to-value (or you can request it dropped at 80% loan-to-value with an appraisal) whereas FHA it's on there for the life of the loan. 

There have been some very good spreadsheets posted on here in the past that you can search for and find.A spreadsheet is going to be much easier to use and play with different numbers than an app.

Multifamily property management is quite different than single family, I have done both. 

Everyone's situation is different and so are state rules.

It has different challenges.