It's a fine balance between economy and what you would do for oneself, but creating a space that feels like home should be of primary focus.If you're looking for some insight into re-leveraging any investment properties for capital improvements, furnishings, etc, some lenders can utilize AirDnA projections to qualify. 

I obtained a signed pre-approval from a lender for a short-term rental (STR) investment at 80% LTV.

The next steps will involve accurate construction cost estimates by a licensed contractor (or two) and connecting with a lender (possibly current local bank) for construction financing.

Did you work with any real estate professionals (agents, lenders, etc.) that you'd recommend to others?

You're chasing 5-star reviews. 

Perhaps I can find a private lender or use a Hard-money lender.  

If you have not submitted it to the Association, review your bylaws and condo declarations. 

The preliminary analysis can have lots of data, so it's important that the provider thoroughly review it with you to explain what depreciation tax deductions Cost Seg study provides and what depreciation benefit you would get w/o Cost Seg.

I think there are a few private money lenders in our group including myself, people are always needing funds, and there's a few wholesalers that also are passing deals around.

Otherwise, if your cleaner feels stressed about talking compensation with you, feels under paid, or otherwise feels stressed about the relationship, it's going to impact your revenue in terms of reviews, and likewise cause you to have to replace them soon.