I have heard vented units don't dry as effectively but haven't heard any complaints from my tenants and believe the technology continues to improve.

With those, the HOA fee's usually have a big negative effect on cash flow. 

Sometimes, buying an existing property can be more cost-effective and less time-consuming and maybe require slightly less permits, etc. 

Most STR markets have seasonality, and there are untold issues in the future that will effect cashflow. 

I'm looking to categorize my buyers and blast out a text message to specific groups whenever I get a property that fits their criteria.I'm sure services like this exist out there but I'm looking for the most cost effective one and I'd rather hear the best from you guys rather than from the salesman pitching their product.Does anyone use a platform like this and how does it perform for you?

I'm going to reiterate what's already been mentioned above, but I'm going to actually give you examples of why it's relevant to you to find a U.S. tax professional.1 - You're going to need to file U.S. taxes once you have property down here, there's federal filings, state filings, and sometimes local filings too2 - Tons of tax treaties between the U.S. and Canada that are easy to miss and can cost you a lot of money (important one with rentals - effectively connected income - if the professional you talk to doesn't know what this is, run away)3 - The amount of days you spend in the U.S. needs to be tracked and if you go over a threshold, all of your worldwide income could be taxable by the U.S.4 - Selling real property means up to 15% of your sales proceeds might not be available to you for years (FIRPTA)5 - Lots of nuance at the state and local levels, which both want to take as much money from you as possibleMain takeaway here is that you should find a U.S. based tax person.

Are cold calling or broker relationships more effective?

Raleigh is in a flywheel effect. 

I’d love advice on leveraging my existing assets, navigating seller finance deals, or other tips for scaling effectively.

From experience, finding a knowledgeable accountant is key for handling taxes effectively, especially when splitting expenses, claiming deductions, and managing depreciation.