Then the arguement is of cash allocation can you make a higher return on capital by paying off your mortgage sooner than investing in _________.

-Allocate a portion of your funds toward extra payments on the current mortgage while also setting aside money for a new investment.

My recommendation, depending on income, is to get 2-8 total properties per city and really allocate 40-60% of your intended investment before moving to the next city.

Hello,You should have the security deposit allocated to a specific business account. 

Then they said that I couldn't get the 10k USD back because "the funds had already been allocated".

i agree that a new purchase at 75% equity will typically not have significant cash flow and may even be negative when properly allocating for all expenses.Investing to max equity without reserves is risky and you indicate would result in stress.  

I mean do I consider it as a regular loan/mortgage and set a certain amortization period to be able to calculate monthly HELOC interest  payment, and allocate as % to the "principal payment"?  

Also, don't deprioritize building a financial cushion by allocating a portion of your income to an investment fund for down payments and property improvements.

I beleive offering buyer agency fees will ultimately be where sellers should allocate most of their marketing money, not in listing fees. 

While you shouldn’t categorize all tenants and it’s the landlords responsibility to properly screen, the tenants who reside in better situated housing and pay higher rents are more financially responsible meaning lower rate of rent loss and will generally take better care of the property which combined will result in less time allocated towards management functions if self-performed or more favorable management fee structures if 3rd party management companies are utilized (which ties back to #1, as well).