Right now, I am curious about, but not anything close to sophisticated on, office, especially in the suburbs of Denver where I live.

I have a C-Corp (no assets) as the Prop Manager  to manage leasing and rental collection for all 4 LTRs.

We have a judgement but since they closed their offices LLC that entered into the contract we have no way to collect.  

Build 2 or 3, get them running, collect some cash-flow, and see how the business goes.

Cross border taxation is very complicated, most developed countries like the US and Canada have sophisticated systems to ensure their residents pay taxes, and you are not likely to be able to achieve your goal of not paying Canadian taxes on Florida income while a Canadian resident. 

Hi Shawn-Congratulations on starting out on your real estate investing career.You have a question about whether it is good to have your real estate license or not as an investor and you are leaning toward multifamily investing.I personally think having your real estate license is helpful as an investor.Having your real estate license allows you to work with other investors to help them build their portfolios which helps expand your network while being productive, you can research market value more effectively, find out about deals before they are listed, and of course it allows you to collect the commission on purchasing any listed property.To Your Success!

If so, then I would return the portion of the security deposit to the one leaving and collect that same amount from the one staying. 

And typically long term rentals don't make it easy to include property management fees into the numbers and have them still work well.I would consider looking into STR type areas where you can avoid the risk of property damages (str and pm insurance covers almost everything that they might damage) and evictions/collections.   

In a few of the states there is either a form. you must sign or an application that your escrow closer must file in order to exempt from any state taxes or withholdings that might normally be collected at sale . 

I actually collected the differential of 7% interest on the $50,000 note (this was an interest only note - not amortized) for 18 years!.