"What harm could adding lights and hauling in a stove do to a lender?

Don't worry it won't do any harm.

I do not know the legality behind not being able to change locks if the property has not been occupied, but do not see the harm in trying to secure your property in the meantime.  

No harm in asking to sort it out in your head.

We don’t know any PMCs to recommend in the area mentioned, but since selecting the wrong PMC is usually more harmful than selecting a bad tenant, you might want to read our series about “How to Screen a PMC Better than a Tenant”:https://www.biggerpockets.com/member-blogs/3094/91877-how-to-screen-a-pmc-better-than-a-tenant-part-1-services-and-processesWe recommend you get management contracts from several PMCs and compare the services they cover and, more importantly, what they each DO NOT cover.

It proceeded to segregate them - isolate them so they couldn't do my computer any harm.

Please keep in mind that I'm acting with the best intentions, and mean no harm.

If it has been listed on the market for 2+ months, then I don´t see the harm in making an offer under the listing price.You´d have to wonder why it is listed so far below market value in the first place though.

Sub2 deals aren't that complicated, but you do need to understand what you're doing, you can do a lot of harm to the sellers doing it wrong and some states have some laws in place because people have gotten burned. 

As long as your very clear on what you will do once you get the person to call, then I say no harm, no foul.