If that happens you could easily have to fork out $5,000 to fix the place up (Speaking from experience here), plus you could lose that rental income during this period.

Be aware that you'll likely lose 2-3 of your renters along with your current rehabs over the first few months.  

It's possible to actually lose money with all the fees plus you time.

So there was really no reasoning with him, he seriously believes he doesn't have to pay taxes.My question is is there any way I can ensure to be in the first position to buy the tax certificate so I don't lose the property?

If so, figure on losing about 20%-30% through collections losses/leaks.  

Also, with spring coming, I may lose out on a longer term tenant.Opinions on whether I should take these tenants( assuming regular qualifications are met)? 

Doesn't sound like much $$ to lose, but I have heard that they spend the majority of the time "up-selling" you on the next big event or other "stuff."

Where it is advertising on those social media platforms, funneling prospective sellers to my website, I would like to bring in distressed home owners to the sight where I could purchase the home.  

It's all losing large amounts of money to be popular.

They know they'll lose money if they go below that so that is your 'bottom end'.