In our opinion, Class C tenants have FICO scores from 550 to 600 - where their chance of default/nonpayment is 15-22%.

But it is my opinion you should try Airbnb, VRBO, booking.com and FlipKey and give it a chance to see if it is adding business.

•Exterior: Landscaping improvements, including tree trimming and shrub removal.

There's a good chance the issue(s) you face has already been discussed and answered.Ask questions in the appropriate forum.

For multifamily deals, positive cash flow often comes from finding under-market rents where you can add value through light improvements or operational efficiencies.

To this very day we are still taking on new clients and are doing just fine, so it goes to show you can’t please everyone but that doesn't mean you can’t still do good business and improve.

Before listing it on an STR platform, I need to make some improvements to my current home.How can I maximize tax write-offs for these improvements?

Quote from @Aaron Kuehmichel: When the tenant requests an improvement, it's OK to say no.

If in the rare chance they do allow short term rentals in the HOA rules/regulations and association documents, don't be surprised if they change that ruling after you buy. 

Real estate needs to make at least 15% to make the effort worthwhile and have a chance for >20%.