[Captain Obvious moment]: Regardless if you go with an on-demand or a storage tank for DHW, insulating your lines makes a huge difference.  

Has anyone tried buying sheds from Costco/Home Depot/etc and then renting them out as storage units?

The constable service we use in Indianapolis not only shows up to remove any persons, they also photo document all remaining items and take them to a local storage unit.  

Attempting to purchase a storage unit this week.  

I bought them originally at HD/Lowes sold as garage storage cabinets   Or should I leave it to let the tenants use them or, take it with me / sell them ?

This should give them time to make plans for other housing and storage or sale of the personal property.

I have a friend and client who is in hopes of building a boat storage facility in Sante Fe, Tx.

Garages matter here with snow and also for storage. 

Immediately upgraded the common areas (land scapaing, new hand rails, fresh new paint colors, refaced the storage units with wainscoting, cleaned the garage so people could park easier, etc.)3.

Water issues in a basement can be caused by a number of things:a) Gutters clogged - easy fixb) Improper grading around the building - more expensive fix but still not that complicated.You could build the tenants some quick and dirty of the floor cabinets to use as basement storage and mandate that everything must be stored in the cabinets -- nothing spread around.