If so I would do a feasibility study to see the need and call other local storage facilities and see how crowded they are.

A multi family property for around the same price which is very feasible in this area. 2.

As for house hacking, that's something I've become pretty familiar with and I'm definitely interested, but I'm having a hard time finding feasible duplexes or other similar property types to make that work in my current place of residency (Bloomington, IN.).

If the house is on a basement or crawl, adding a bathroom may be pretty feasible.

Depending on the timing of your sale and the extent of construction you need to do it may or may not be feasible for you.  

Managing the manager" sounds good in books and real estate school but does not work so well in real life.Buy right, expect inefficiencies, and (prudently) scale as quickly as feasible.

Can single pieces feasibly be replaced?

Is it feasible to work with an investor/contractor to build the 4-plex with a guarantee to sell to me after the project is finished?  

I don’t know if this is really feasible in practice though, and I certainly do not recommend abusing it.

@Christopher Mosher, I agree with @Jonathan Marcus An architect can help you determine what is actually feasible to build.