We are not privy to the purchase agreements, assignment agreements and security instruments used to buy and sell this deal.

Notes are financial instruments and need to be looked at primarily as such.

(However, if you buy another property right your total cash flow will increase)A HELOC really is a short term instrument. 

That's highly doubtful.There are trade offs for liquidity.If a fund is more liquid than others, it goes to follow they'll have more capital in instruments that are easy for the fund to liquidate (e.g. money market, CDs, short-term treasuries/munis).The ROI of all of those asset classes is negligible and (currently) below inflation. 

State that X person (usually a Member, Manager or Officer, but not always) is authorized, in that capacity, to execute all documents and instruments necessary to effectuate acquisitions/transfers of properties in which the LLC is engaging or involved.

@Andrew Cornstubble I agree - so many of my personal and professional connections have been instrumental in my career so far!

BP has been instrumental to me too!

That said, a HELOC should be considered a short-term debt instrument. 

Some banks just do multiple D-T (Deeds of Trust) filings as security instrument using independent notes, but a master D-T with a release clause in the note is more common.

You will usually be paying a bit of a premium in rate usually 1.00-1.50% in rate premium but the advantage is the original note and deed/mortgage security instrument will be recorded in your LLC's name (no due on sale risk of LLC post closing transfer with a conv/fannie/freddie mortgage).If you want the lowest rates possible then you may want to stick with the agency/conv paper and doing that post closing transfer after you've seasoned the agency note/mtg so that the lender can get a chance to package it up and sell it before you do that title transfer.