Apparently, the theoretical models showed that passive house standards would cost just a little more than normal building costs to get much better energy efficiency, BUT when it was actually put into practice it turns out that the passive house building codes cost LESS than the previous standards to build and are more energy efficient.  

I suspect there's so much vacant land in TX this model just won';t pan out

I’m estimating the re model will cost 10k (so plan for 13), and the additional property about 17K with around 10k re modeling.I’m unsure if I should seek two loans one for each house or bundle them together.

Both are great models.

The answer is to change your model slightly from a fix n flip model to a fix n rent n evaluate model.  

No problem getting them financed.I suspect this is a hybrid of Manufactured home and stick built add on .. not sure where that falls. but buy a manufactured or factory built home and affixing it to a permanent  foundation creates a home that is financeable like any other.. at least in all the one's I have done.. and will continue to do in your fair city.Also in Charleston SC were I am quite active there are a lot of factory built homes.. they are different than the west coast trailer style but none the less they are factory built.

@Dustin PallsIf you do a remediation/abatement style removal then yes you are liable.

I'm considering a 'rent to own' model for my current 1 bedroom carriage house.

My new adopted model is "live my personal life like Dave Ramsey and invest like Robert Kiyosaki"Thanks for reading this short essay and I hope to get to know all of you on here!

Home ownership is a lifestyle choice not a investment and is far more expensive than renting.It appears your life style choices are driving your decision making process.