I know there have been numerous recent apartment projects completed in the past 6-7 years which likely contributes to the available units.

I've contacted the property management company on numerous occasions to see if the tenant will be paying but have not heard back as to whether the tenants have responded.

I found numerous calculators, but none that will allow me to include the balloon payment at the end.Thanks

We did it numerous times. 

So I hired a contractor to come clean the 40' long 10" diamater tree branch off the roof and numerous other branches leaning collapsed fences, I hired another contractor to come fix the roof leak. 

There are a few mentoring programs that have various different levels that are not more than $10K and BP has numerous threads about the value of different mentoring programs.If you're not going to invest in a mentoring program and still want to seek a mentor, then bring something of value to those individuals. 

There are numerous articles on the internet that talk about this perceived issues and reputable ones disprove any problems.

It's tax law, so there are numerous exceptions, restrictions, and extensions on that "section 121 exclusion", but that's the general concept.)Since the property was gifted to you, you have the the gifter's basis in the property.

Just providing information that will "solve some buyers problem"   From numerous BP podcasts I have heard to always try to solver another persons problem.  

No unfortunately not, if your main source of income is active real estate investing and doing numerous deals per year, then its considered income.