(The point is to begin making passive income; but a lot of emphases is on "living for free" in your unit, while the other tenants pay all costs).

A close relative of mine is going through something similar now, and has no money because of the divorce, but was otherwise very responsible financially, so I can emphasize with her situation.

I can't emphasize that enough.You're in a great position to leverage a decent chunk of money into a lot of money.  

But, I emphasize, that's because I don't know the terms of the purchase you are considering.

I emphasize with TK companies who only do cash deals as financing typically slows the deal since in essence the seller is having to sell the mortgagor/financer on the deal as well.

This increased liquidity is hard to over emphasize because it adds value to your investment and provides you with better flexibility, especially when the market is taking a turn.RENTAL PREMIUMThe vast majority of renters would prefer a newer home.

I appreciate you emphasizing situation AND goals.

IRS has briefly mentioned this issue inRevenue Ruling 73-410, 1973-2 C.B. 53, Private Letter Ruling (PLR) 7941002 (June 25, 1979), Chief Counsel Advice Memorandum 199921045 (April 1, 1999).All emphasize that the segregation of cost to determine the 1245 property is factually intensive and must be supported by corroborating evidence.In addition, an underlying assumption is that the study is performed by “qualified individuals” and “professional firms” that are competent in design, construction, auditing, and estimating procedures relating to building construction.Also, IRS has entire audit guide at: https://www.irs.gov/businesses/cost-segregation-audit-techniques-guide-table-of-contentsThey will make sure this is done correctly so better to get professional.May be @Yonah Weiss can answer better. 

I can't emphasize this enough, start credit as early as possible, but the key is to be responsible!

A qualified residence means the taxpayer's principal residence and one other residence (second home) of the taxpayer selected to be a qualified residence.The reform bill also includes limitations around the amount of home equity indebtedness both by itself and relative to acquisition indebtedness.I would emphasize my original comment, consult a trusted tax advisor before using home equity loans as an investment funding strategy in tax years 2018 and beyond.I imagine this new bill will be keeping our tax people fully engaged for a while!