I just checked out your profile and I think the fact you own investment properties yourself gives you a lot of credibility among other investors looking for management help and that is something I would not be shy about sharing. 

Most improvements will be just cosmetics such as flooring, kitchen(cabinets, countertops etc.), lighting etc.

Tenants want to stay and really don't expect any improvements to be made.Thank you!

It’s an improvement of the property.

And I am small time(for now) I work out average rents by street and building and what improvements that might be justified by additional rent.

Steven, the idea was to make the deal attractive to the sellers, but how would you restructure it to improve my situation and still be persuasive?

Do a quick search of "newburgh ny crime", in 2015 it made the top 10 most dangerous cities in America...looks like it's improved a bit since then.  

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. 

I budget 10% for vacancy and 20% for maintenance/capital improvements.  

Your position on this item will be stronger if your lease has language regarding making unapproved repairs or improvements.2)  I think you fill those holes with mortar and move on.