There are a bunch of different figures associated with this decision, such as new interest rate, old interest rate, cash flow of new property etc, but I'm having a hard time getting my mind around how to analyze the decision mathematically.  

Every individual contract is different.

They won't always be upfront about this with you but if know they're selling because they want to retire, that opens you up to different options vs if they're an investor just selling for profit.

Prices will certainly vary between different tax firms.

The only difference on paper is that the deductible for hail and winter storms is 5k instead of the 2,5k that I have with Farmers. 

now, if you want to buy an STR as an investment, and you NEED the income to support it, that's totally different...

This is a pretty critical difference.  

==========================My relative is asking if this is a viable way to legally avoid having to pay taxes:STEP 1: SELL PRIMARY RESIDENCE (House A)-Sell primary residence to son-in-law for cost basis + $500K-File gift tax form for difference between sale price & market value-Not pay capital gains on $500K due to personal exemption.STEP 2: SELL RENTAL PROPERTIES-Do 1031 exchange and buy House A back from son-in-law-Rent out House A for 1 year before move back in==========================Thoughts?

Does it make any difference that my wife’s mother which is the executive of the estate only owns 50% of the property we want to acquire?

To achieve this, I’m planning to scale rapidly by performing a couple of syndications to acquire a larger portfolio.I currently have a portfolio of 17 properties, but to justify labor costs and create a sustainable structure, I need to expand quickly.