May be worth posting in the BP classifieds for specifically what you're looking for!

The best way to get a deal funded is in the classifieds post it will all the specifics to the deal.

My bookkeeper will know that any transaction from that checking account is associated with that specific property and eventually they all come from there.

I don’t think 1031 exchange on a primary is legal 

However, it is important to consult with a legal professional or tax advisor to ensure that this arrangement is feasible and complies with all applicable laws and regulations.

Consider talking to an insurance agent who can give you specific advice for your situation!

Would you recommend any specific places to learn/research these?

If you have a specific question just ask. 

Thank you,Matt MortgageNewsDaily.com is a very good resource for daily tracking of conventional rates and they also have good content explaining the reasoning behind the moves (MBS, treasuries, etc.)DSCR Loans a little harder as its going to be a range and based more on deal specifics, I'd check youtube, etc - also would generally track the 5-year treasury yield and add about 3% to get a general daily ballpark

You need competent legal council.