Likewise there is an “assets” consideration to think about.  

The one that I am most concerned with right now is the ceiling height.

We don't know what states the properties reside.Florida, Georgia, Hawaii, Illinois, Indiana, Montana, South Dakota, Virginia have different laws.Oh, and by the way, an attestation to the insurer and others (mortgagee) will not change premiums nor constitute a “sale.”There are considerations such as the loss of asset protection after judgment (beneficial interest is personal property, not real property), but if the property is clear of a mortgage and the concern is title theft (a concern you raised), then putting the property into a land trust is probably a lower cost alternative to maintaining a debt (which irritates the wife). 

Things like number units, height, area, number of stories, etc are all specific to a building’s lot.

Robuilt has some youtube videos where he covers these tax considerations.

I also really like that this is a U-shaped window unit which wraps over the window sill, meaning that you get to keep nearly all of your window's view and natural light, as well as it being theoretically harder for someone to break into the apartment by kicking in/pulling out the AC unit (ours is on the second floor, but the safety concerns for first floor units is definitely a consideration you'll want to factor in).Heating.  

I see it being the same height as the current window, and running from entry side of front face to window.  

IMHO.Not that I will take them into consideration, but I appreciate your thoughts anyway...... :-) I other words, Bruce doesn't believe math has any part in investment analysis. 

If it will cost you considerably more in the future and loss of appreciation, lose of tax writeoffs and lose of cash flow in the meanwhile, than the amount of debt you are paying off, how does that put you ahead? 

50% down is considerable but common.