I know that rule is federal for owner occ.. how about investor notes or commercial notes.. ??

You can do HELOCs on rental properties through Pentagon Federal CU ("PenFed").

Since 1031 is a federal statute it has the same requirements in all 50 states and most good intermediaries have a national presence. 

This is one of the credit that federal as well as state extended to RE dealers and investors. 

@Justin Hamilton at The Federal Savings Bank is my go to lender partner.

The first option with duct work seems more expensive and intrusive to occupied units.Unfortunately there is no natural gas available nearby to tap into, which is of course my favorite way to heat.Any thoughts or advice in this area would be appreciated.Also curious to know if anyone is familiar with federal or state (we are in MD) tax breaks or incentives for improving efficiency of a building, or converting from oil heat. 

Under Sec. 453 or the federal tax code, with an installment sale you defer tax on all capital gains tax, including any depreciation recapture from straight-line depreciation.

The Federal Gov’t has two more interest rate hikes scheduled for Sept. and Dec. this year.

Your note/mtg can say anything it wants, you still have to follow state/federal law and procedures.  

It does not have to be in the entity  ( LLC and S-crop) CA has not enacted any legislation in response to the new 20% deduction, so it is still not sure CA will actually give you the deduction even if you qualify on the federal level.