Mortgages in Canada come with different terms (eg 1 yr, 2 yr, 5 yr) and fixed and variable rate mortgages. 

If they are legitimate, it will be trivial for them to sell the currency and provide you funds in USD. 

We have a interest rate around 3% on the SFH, purchased in 2021, so doing any refinancing with that doesn't seem to make sense.

I am not house hacking.This means that’s I will get less favorable rates AND will be covering a HELOC + second mortgage with the rental income, which seems difficult.

And vacancy rates may also increase because of the amount of bureaucracy you have to go through to place a new tenant.So again, a lot of variables.

My goal is to start learning and hope to buy my second (we own our current home) property within the year to start my real estate investment journeyI got interested in Real Estate investing because I want to be able to have a large family and give them everything they need (college tuition, family trips, emergency fund) and want to grow a portfolio with constant cash flow to allow for these things. 

, it’s not ideal for getting funding.

Here's a bit more in detail about how rates are calculated for DSCR loans:1.

On paper cap rate looks good and I've heard there's a hot rental market, but not sure about in practice and what quality of tenants we could expect.  

5 star ratings are significantly dependent upon your cleaning crew.