This looks to be a job that would take less than a day with minimal disruption if done by a qualified contractor.

I'd like to upgrade the property before refinancing it, but I wonder if I should disrupt the tenants to do so.  

Millennials have been brought up in a society of “NOW” and “instant gratification,” and this has become the catalyst for disruption to many markets, including stock trading, the taxi industry and retail, to name a few.

It's your property and your choice, act or sit on your hands out of fear and let her disrupt your life.

Our contract says something boilerplate about tenants can't disrupt the peace of other tenants. 

If it is legal to operate the business and won’t disrupt other tenants, maybe it is worth considering.

I want to make sure I do this right and with as little disruption to the tenant as possible.

If enough police cars show up to your place it will disrupt business next door and they will move to another location.

If possible, try to group showings to minimize the disruption to the current tenants. 

I personally believe the latter is critical; if you self manage you take on the risk of those events (stopped toilet, whatever) disrupting your life.