There are governmental liens that are not extinguished via the tax sale; IRS, city mowing, child support, etc.

In our state (NC) the “standard” Offer To Purchase and Contract form (NC Bar 2-T) supports seller financing via line 1(d) entitled BY SELLER FINANCING and the accompanying Loan Assumption Addendum Note though that virtually no NC brokers will entertain a lease with option to purchase deal because the old “standard” form for this kind of transaction is no longer available from the NC Bar, NC REC, or NCAR.

Remember Paint is just colored glue.You can scarify the concrete to remove as much as you can and then encapsulate the  concrete with a portland based self leveler ; Ardex, Mapei are a couple of national well recommended brands with good tech support.

There is a wealth of information and support available throughout the site.  

I don't really want to do a 1031 transfer because I will want to be able to pay my grandfather back his investment then use the proceeds to start another project without needing an investment support the next time...

As for the question about oil prices, I would agree with @Richard Spooner that Houston will not suffer this downturn as much as it did in the 80's due to so much more diversity in the types of industry that are now supporting the region.

My DTI (debt to income) ratio would not support a higher purchase point.4.  

Thanks for the quick responses and great support, BiggerPockets is proving to be a great community!

I have a key emblazoned with the University of Florida logo, I'm sure someone else has the same looking kind of key. 

In a university town like Madison renewable energy is a big advantage.