Here's a very helpful article by @Scott Smith on LLCs and pass through taxation.

(such as things that can reduce taxation both in US and Canada)As a beginner, should I independently finance or take a loan and buy more units?

You better check that out, CA assertion of LLC taxation is massively broad (both CA and out of state formed LLCs), especially the minimum tax charge.

I would reach out to @Jake Hottenrott He's a REI specailized CPA and also has a REI Specialized CPA who also focuses on Expat/international taxation as well. 

We live in Canada, and she does not hold any investment property because we heard some horror stories about dealing with US taxation.

I heard that 1/4 of all the money in circulation, was minted in 2020, so if this true,  I agree with the person that called it double taxation. 

Then at the point you can buy it and cash her out she can pay tax at that point but in the mean time she gets tax differed income with no management issues and you have a bonafide equitable interest.

Each state may have it's own rules for taxation.

Joseph, I recommend finding an accountant that specializes in real estate taxation over one that is local.

There's worse things than paying some tax at 80.