The down payment is from  a HELOC- The expenses are below. 

If you're in the 25% federal tax bracket, twice the tax is extremely expensive.

Also, a good reliable team of contractors is needed to quote you for possible expenses.

Do you have any suggestions on how to educate myself before jumping in to purchase something and then being hit with fees or extra expenses I'm not prepared for?

As for expenses, since I don't have real numbers I just used 30% of Gross Income. 

I am looking to pick up some apartment buildings in Newark, NJ and would like to immediately re-position each building by managing the expense side. 

Last but not least, generally speaking HML is expensive.

Maybe offer some help with moving expenses or guarantee a full refund deposit if they're out by a certain date.

It's not that expensive and it helps maintain the property and eliminates complaints from my tenants 

Assuming a 6 month, 100% loan for the purchase price at 11% per year plus 2 points, as well as 15% interest for the full rehab, here is an estimated P&L:Don't mislead yourself by focusing on the spread between the purchase price and ARV, as many new to the business seem to do, ignoring all expenses.