They let you use the tools and make your own furniture in off hours, but learning the techniques and how to is a craft that as a culture only a few have kept up with.

I'm still in early stages of researching this, but it looks promising and there is case law to support this technique.

You need to know LL tenant law, screening techniques, fair housing laws and on and on. 

Does anyone have any tips on how to create maximum soundproofing between upstairs and downstairs, whether it's using certain materials or certain construction techniques?

I'm one of the rare individuals on this forum that is not interested in enlarging my footprint and can see myself selling in a few years so my goal is to increase property value.

If $272k is too high for your investment return requirement, figure out what is right for you and offer that (or maybe a little lower, depending on your negotiating technique).Good luck!

I don't have Comp 1, Comp 2, Comp 3) that I felt were most similar (using J Scotts comp. technique).

Explore alternative framing techniques/materials to the traditional stick framing that may be cheaper or provide better value over time given the high lumber costs (ICFs?

Lastly, the boots on the ground technique of just driving a neighborhood is a great way to get the feel of the area.

There is also built in principal reduction to the mortgage if you do this consistently as your monthly surplus is being funneled towards reducing the HELOC balance, which is why sometimes it's called an accelerator technique.