You've unfortunately unlocked the centipede effect by saying Columbus.

The 1st position heloc has nothing to worry about because it will still be attached to the property after the 2nd position heloc forecloses....death of the borrower has no effect on it.Likely not time to make a deal with the “owners” since that would likely involve probate, and time.  

Biggerpockets folks will advocate for real estate as a long-term investment and I'm no different, but while you're thinking about it, I'd also recommend you consider and research treasuries through treasurydirect.gov while rates are still relatively high. 

What's the most effective means of dealing with this issue?

Its much more cost effective to outsource things like skiptracing and direct mail.

Read: The millionaire real estate agent; Hyper Local Hyper Fast AgentWhat are some effective ways to network with individuals at all levels?

It's just a single family home so the rents don't effect the appraised value.

It reduces the “bouncing ball” effect of tasks being passed between departments. 

They will confirm to you that the number has been steadily increasing year after year (Covid or recession effects aside).

Effective  12/1/2024 @ 12:01a the Louisville rental registry requires the 16 page Lead Hazard Evaluation form in addition to the Affidavit of Compliance.