A small percentage.  

Again, this was just based on my one experience and there are other variables that play into the equation, especially your particular state's laws. 

Then I look at Percent Renter-Occupied to see what the rental market looks like:It looks like Kennesaw has a smaller percentage of renters than Acworth, which still looks good.

Real Estate returns can vary also but the percentage of gains are usually higher from anywhere around 4-8% on the low end. 

Assuming their gross income without the $125k would be <$50k, could you advise on what percentage or amount of income taxes (& any other costs) that she must pay by cashing out?

@Jacob PereiraHey Jacob, Im not sure about your current investing experience but you can always look just outside your major city limits for something that is only a small percentage of your capital that you can pick up for a deal and go trough that process even if you dont make your ideal ROI, (Dont lose money by any means), but that you can get trough and essentially buy yourself a hands on education.

I would, however, ensure to be upfront with whomever you work with as a very small percentage of sellers will be willing to entertain seller financing. 

Determining whether to do a cost segregation study or not has a lot variables.

THEY DONT TAKE A PERCENTAGE of your payments!!  

The government is seeking to avoid mass-scale loss of shelter for citizens as every percentage point of unemployed and/or not-housed individual has an inherent cost elsewhere.