Loan interest is deductible based on the use of the loan, not the asset securing the loan. 

The other route you can look into is purchase+rehab loans if it's going to be a primary, if it's an investment then using hard money, bridge loan, or DSCR.

This should roughly take me to 150k per year and carry the loans for land and construction.

Possibly break loan covenants and can't cure default, lender takes back property.  

If you're a single mom with student loans, a car payment, and living paycheck-to-paycheck, then $20,000 would be devastating and a reserve is critical.

Consider a 15 year loan.

I ended up having to pay for their tax preparer’s time to (finally) meet with me and make corrections.

I've seen estimates that are off by 300% when all said and done (e.g. the original bid was $10k but the final cost was closer to $30k).

We generally advise our clients to go ahead and pay the recapture rates if death is the alternative.The good news about recapture - the deductions are a deferred tax liability to you, and an interest free loan from the government.

Do you use traditional financing or do you us DSCR loans?