It's just that I'm anticipating a "better" tax situation next year - that is, for personal medical reasons in my family, I'm anticipating a lower level of income next year.

An exemption is offered for the first $50k of Florida source net taxable which helps a lot of small businesses. 

Not exactly:If you moved out in 09-14 and you move back in now, until 09-19, that year up until 09-14 drops off as it wouldn’t be within 5 years.Also, since you lost the 121 exemption in 09-17, if you moved back in for the 2 years you’d need, you wouldn’t get the full exemption.....it would be prorated based on the number of years you did occupy verses those you didn't.In your case, at 09-20, it would be about a 2/3 exemption (8 years verses 4).Also important, the 121 exclusion only applies to the Half you lived in.....the other half is treated like an investment property.You’re also going to have depreciation recapture on the other half, plus your half while it was a rental.  

Forgot to mention.....usually when zoning changes the “non conforming use” is grandfathered in with some restrictions.....if vacant for a certain amount of time or if destroyed, the exemption for being grandfathered in goes away.

Are you sure it isn't medical? 

Be it our job is tearing our family apart or we get medically separated. 

See if you meet the requirement and get an exemption.

Moreover, most of the people living in these areas drive 30 minutes per day to downtown Houston and Houston Medical Center.  

My question was whether an accessory structure (NOT dwelling unit) triggers this requirement.As another aside, yes there is a permit exemption for storage buildings below 120 sqft (that are NOT on a hillside or in Fire District 1), but it still has to comply with all zoning and other regulations.

Know that taxes are higher without a homestead exemption.