Also of importance is that the seller passed on the security deposits of current tenants to me at closing.I know that in Florida once a contract is executed any damages that occur to the property before closing are the responsibility of the buyer and this is why we buy insurance during this period.

It must be ok though because the tenants would never get through the security at the gate otherwise. 

What are the equivalents to “www.cozy.com” or www.rent prep.com” etc, what systems can be used in Canada to set up rent collection, security deposit and other payments?

The attorney should have made sure the leases and security deposits were transferred to the buyer at closing.

Any or all of these can be a security governed by state/SEC regs. 

Traditional financing, but I was able to secure a 15% down payment on an investment.

I was a bit confused by this, since it's clearly built as four identical apartments - each with a matching layout and full kitchen plus a main entryway with a shared staircase.

I've always been told appraisers are supposed to be looking for the (3) S's - Safe, sanitary, and secure. 

First, unless the mtg has a PR provision, and unless the was a real estate related loan as opposed to a loan for the operation of the primary business of the corp, it probably does not, the lender doesn't have a contractual way to value the property as an asset securing the debt making setting a PR price difficult. 

Most property management companies do all your accounting for you and send you reports and direct deposits into any account that you prefer if you go that route when you add in more doors.On a side note, It depends on your state as to how your rents and security deposits are kept, so good to check the statutes out an dmake sure you adhere to their guidance.