It would depend on location and "category" (a C level vs a B level for instance).

For instance, a duplex can offer more consistent income since if one tenant vacates, you still have another paying rent.

Alternatively they can purchase a portfolio of occupied homes at a discounted price because the seller of the portfolio in most instances first tried their hand at selling the homes individually to the owner occupant and after experiencing 13-15% in disposition fees and expenses realized its not worth the effort and better to package the assets and sell discounted to another investor.Keep in mind, most of these SFH's are in stagnant markets meaning limited appreciation and if you ever took the time to look at an amortization schedule  there's no meaningful principal paydown for many years.

In my almost 20 years of doing Subject 2's and working with other investors in almost every State in the US, in the very few instances the Due on Sale is called it is because if the inexperience of the Investor in not knowing how the transaction is to be done, (not closing with a Title Company or Attorney, not doing the Insurance correctly)Most of all, (not communicating with the seller) Bank calls the Seller to offer them Life Insurance or some other service, and the seller tells them, "I don't own that house any longer, some guy took that house from me and put some renter in it"If you dig into any investor that tells you they had a property or a friend of their brother in laws Collage roommate that had the Due on Sale clause called, you will most likely find that the investor screwed up somewhere.This is why Education and knowledge is needed on any Real Estate transaction.I get calls almost everyday from someone who screwed up on a Subject 2 and is asking to be bailed out, many times they do not want to pay for help, and things just get worse.If you know how to make the Bank Comfortable with the transaction, all is good.Last year I had a couple of hedge fund managers call me asking how they can offer their under preforming loans to Investors to by Subject 2, wow what a great deal, I could call Pace and he would have buyers the same day for a 1,000 homes, but the legal aspect of this would hold the Hedge fund liable so we could not do a deal.

There are also ways to go about mindset shifts if that's a serious issue, but I don't know, it sounds like you've spent time with this property, you know all about it, and you have a bunch of other stuff going on in life.For instance, you decide not to raise rent all the way to market rate....This is probably a good move if you hate maintenance calls and your tenants know to handle some maintenance themselves because they are getting a bargain deal.

For instance how the particular municipality examiner will interpret and review the plans, how your neighbors or someone with standing may respond through an appeal etc. etc. 

Especially in blue states, if you’ve gone through an eviction that generally takes multi months, it’s a clear indication of poor behavior in most instances.

The rate on a HELOC will fluctuate with the market whereas a cash out refi rate will be fixed, so it depends on your risk tolerance in the instance rates were to go up. 

There was a big, very famous lawsuit that ended price fixing in real estate.

It was a rare instance when a Section 8 tenant moved out of one of my rentals in Oakland.