OR PUT THE WHOLE AMOUNT AND PUT IT IN THE RENTAL UNIT TO TAKE ADVANTAGE OF THE TAX CODE?

I wouldn't play the game of applying some of the cost of the rebuild to your personal residence to avoid bringing it to flood code.

If the bedroom windows are boarded up that’s a building code violation when it’s occupied.

They will coordinate with a title officer to get the survey and change the tax numbers; with a contractor to adapt the entrances or meet current codes; with everything to be seen on paper for approval.Location is what is going to determine your process steps.

Depending on when that building was originally created, you may be forced to bring other aspects of the building up to code which can drastically change your budget.

You need to check the building code, because most jurisdictions have limitations on what a minimum square footage for livability may be.

Here is some basic information for mortgagors: Texas Property Code Section 51 covers foreclosure law.

The only way you can operate one legally is in specific zoning codes that allow for such a thing. 

Negotiated with the bank, city code infractions, and owner to purchase the property.

Numbers look good but like @Matt Moreland said there will no doubt be some expenses to get the property up to code.