I typically include $1,000 per year in my analyses on 2-4 family properties unless there is a particular feature that justifies a significant increase or decrease in this figure.

What rent increases (or decreases)  are anticipated in the coming months?  

Track all of your income and expenses in some sort of report form and review it regularly with your employees or Team members that have the kind of talent you have looked for and have the ability to help you to possibly decrease expenses and increase income.  

You can write it down as an expense to decrease your overall tax liability back to the good old IRS.

I had more complex solutions, like charging a variable rent, starting with a high first month's rent and then decreasing afterwards.

(ie. if they don't meet projected earning the market value can decreases).

Reporting the $20,000 of capital improvements will depreciate, so yes it will decrease your income a wee bit and will do so for the next 27.5 years.

Is there any risk of the rents decreasing and suddenly you aren't in the plus on a 100% loan?

If I decrease the discount for booking longer stays my vacancy will go up but I'll have more short stays which pay more.  

We can 'add back' paper losses such as depreciation, meaning that's something that will decrease your tax burden without decreasing your mortgage qualifying income.