Then check recent comps for the sale of vacant lots in the area, similar in size and location to yours, with the same zoning. 

Houses that look very similar on paper (same neighborhood, style, square footage, year built, beds and baths) can have very different market values depending on things like interior light, flow, ceiling height, privacy, yard space, neighbors, curb appeal, master bedroom size, kitchen counter and cupboard space, parking options, driveway slope, proximity to noise or businesses, parks, schools, etc. - to name just a few things. 

. ;-) (this is the one I'm debating because the size fits my yard a little better: https://zipkithomes.com Studio Pod)

But each house on the same street is in different conditions, sizes, lot sizes and do not have the unique feature of a ginormous house garage.If there is any advice you can provide me I would be quite greatful.

So that being said, can ipartner up with someone who can sign up on airbnb as a host to rent my bottom portion of the home?

The good news is claiming income allows you to claim expenses, which means a portion of the house, utilities, etc. can become an expense. https://www.nolo.com/legal-enc...

You should then be entitled to the portion of the estate due to the sister.  

What they are selling for doesn't tell me what they're worth.Are they all the same type (size, location, etc...) or are they different? 

I also heard of one that had a reverse mortgage on it, which does not allow the mortgagee to rent any portion of the property that secures the mortgage - which essentially makes it a single family usage. 

Can you clarify on the size/price of each as well as your anticipated revenue?