The letter would introduce me, the updated rate ($50-$100 increase depending on rate), and a brief explanation of my policies and procedures.

My husband and I currently have 5 rental properties in BC, Canada, and due to our Reno’s and recent price increases in the area, our equity has increased by approx 300K.

Have been running the numbers on a couple duplexes/4 plexes and looking into how I can potentially increase rents once I would take over a property.

It's not too much of a stretch to think this will increase the demand for housing just south of the border. 

Buy the house then wait for it to appreciate 20%The downside is it's highly speculative, it forces you to buy a retail home, provides no income in the meantime, and has high transactional costs.If you get the timing wrong and the market comes down, or the appreciation increase is slow, OR if you get that all to work and then cash out the house THEN the market comes down: you're stuck.

As a result, my agent told me he “made a business decision to protect his client” and he followed the company policy to increase the deductible as opposed to keeping it at $1k which he told me would make my policy defunct, therefore...no policy.I responded that I made the decision to go with this insurance based on the quotes he gave me, and that the increased deductible felt to me, like a bait and switch.He responded with empathy and said that he has done his best and that we should get some quotes on fixing the hail damage.

I'm sure I will have to increase that over time but rent increases will help cover that as well.  

In other words if two people are going back and fourth at $500 increments, drop a $5000 increase on it.

How long can the real estate market sustain increasing home prices?

You need to calculate it as investment income - expenses (including annual taxes and income taxes on your gains) - increased equity (loan paydown - that is part of your profit, but it isn't part of your cashflow)If you are looking at this on only a monthly basis, you'll miss annual or semi-annual costs or seasonal variations.