Unless a property has a non-conforming use permit (NUC), there are only 4 areas on O'ahu that you can legally do STRS.  

Are there other legal or financial consequences I should be aware of?

Redlining IMO would only be an issue if @Jimmy O'Connor said to stay away or refuse to do business somewhere; he did not do that, he just pointed out property characteristics.

The other non-math issues I'm good handling myself. 

This is assuming the way you notified the tenants of the new rent was considered legal notice in your market. 

I don't necessarily need the standard features of pm software, such as rent collection, bookkeeping and maintenance requests, though that could help; but do need a clearinghouse of important information, such as leases, legal docs and other information; maintenance vendors I use; maintenance history; and some kind of tracking system, where I can record the various current projects I'm working on within the business.

Where another issue arrises is I recently quit my job after becoming pregnant as they would not cover my maternity while overseas, my husband is employed however he works for a UK company and is British so would be unlikely to help us with the situation in the US.

Typical renovations include:Cosmetic Updates: Painting, flooring, kitchen and bathroom upgrades, and landscaping.Structural Repairs: Fixing any underlying issues such as foundation repairs, plumbing, or electrical updates.Efficiency Improvements: Adding energy-efficient windows, new HVAC systems, and better insulation to increase the property's overall value.The goal of the rehab phase is to increase the property’s market value while making it an attractive place for tenants.

And Jerry is a Wyoming attorney, so you can trust his legal advice! 

It's usually best to talk with your neighbors about your plans and get their support as one of the variance tests is that the requested relief does not cause a public health issue or alter the essential character of the neighborhood.Try googling "tests for a variance in [your state]" and talk with your local zoning department.