We signed a lease agreement on 12/28/18 and were set to move into a house on 2/1/2019, however on 1/26/2019(the owner had expressed that she decided she wanted to sell the house sooner, about 1 month after signing the lease).

To put it as simply as I can TH and Apt. are going to be easier sell and rent and maintain but you will get more out of selling them as condos.

Luba once demanded that I sell this house "as is", for any money.

And I'm not interested in selling or having a co-owner.

Right now I'm starting with distressed homes and looking for those owners who want to sell as is.

You may have more options on the back end as far as resale, though, because you can sell it to an owner occupant OR investor. 

Will your identified markets be an easy or difficult area to sell once it’s time?

You’re going to sell and owe all that money back.

For example, you wouldn't be able to: (1) take out a mortgage on the property; or (2) sell the property at its market value. 

Could it be because stocks seem safer to some folks since you don't have to deal with them face-to-face or manage them directly?