I have done research on how to use bio filters and regernation zones to keep the pond clean and I have gotten a quote from a local excavating company but I'm sure it's more complicated/expensive than it seems.

There are financial risks and complications.

That makes stuff complicated.

This is a bit complicated, especially for buying a single family home.

I've done some pretty complicated deals since 1999 and they've all been 'interesting,' for sure.) 

I find this significance is often “glossed over” and simply not discussed.The losses that show up on a syndication K1 primarily due to cost seg and bonus depreciation are passive losses and can only be used to offset passive income (with the exception provided real estate professionals as you note above).To my understanding, there are only two sources of passive income:Rental real estateIncome from a business you own that you do not materially participate in.That’s it.Tax law is complicated.

It's not really that complicated.

For that reason, owning the house together will only complicate things. 

Thank you for the feedback.I just don't understand why it is so complicated and that I should feel clueless to calculate the gains tax.

Like many things in life doing simple things well can be complicated in execution.