With 3 properties already, you're definitely not "new" anymore ;-) Doing a refi is very possible (depending on how much equity you've accumulated) to do those types of things...the issue can be the tax ramification that you face if/when you do it.

We have never had an issue but to @Drew Sygit point, we still follow our application and approval process.

Despite this, the worker helped me identify the issue: two toilets with malfunctioning fill valve systems.

Nothing is needed, I never have an issue renting . 

Another issue is there isn't an outlet under the sink to plug the disposal into.

I will also be tracking expenses related to repairs, maintenance, travel to and from NV, hotel stays, meals, gas, and other regular business costs.In the long term, I aim to purchase additional properties under the business name, but I understand I need to establish at least two years of income and credit history before doing so.The issue I’m encountering is that my accountant has not provided any guidance on how to structure this scenario.

They are also looking for code issues and other hazards which hopefully you are compliant with no matter what. 

Instead, I've heard of hosts raising the nightly rate high enough it won't book or setting a 30-day minimum stay and had no issues with a double booking.

Jeez, I would have dropped the biggest hammer I could find right on her.I get scammers are an issue but she is not the police of STRs.

Which is a lesson learned for me because I need to plan things out and recognize issues faster.