The rules say it doesn't "apply to any real property held primarily for sale".

Many syndications don't pay off the loan, so the tax will apply (yes, the IRA is subject to tax! 

Applying for a primary residence HELOC on a duplex, in the range of $110-150k to perform some renovations and use for down payment on new duplex purchase.

I think there is such a huge variance in types of STRs, that you couldn't possibly apply that rule in all scenarios. 

These factors, which should continue to apply to the separate entity test under the check-the-box regulations, include—the sharing of profit from the business;the sharing of losses from the business;ownership of a capital interest or performance of substantial services;participation in management; andrepresentation to third parties as a partnership (including the filing of partnership returns, the existence of a partnership agreement).

When applying for a mortgage I know to give only what they ask for.

You will have to find an agent with an NAID number to place the bidThe closing costs only apply for owner occupant purchases.

I plan on applying for the homstead exemption as soon as the window opens on January 1, 2022.

The funds belong to the Tenant until the lease is terminated and then the funds can be applied towards unpaid rent, utilities, cleaning and repairs, or whatever else your law/lease allows.The same goes for prepaid rent.

During DD, along with finding the real underwriting deficiencies, it became obvious that my back up strategy would be most likely and therefore every basis point matters, since, I will be at the mercy of 3% rent control until tenants move at their own pace, so the lower CAP at close matters more to me, than if I would have been able to apply the primary plan.