I need to file an extension. Should the amount of taxes I paid in 2016 that I enter on the extension request form include the tax credits & deductions?

The amounts you enter on the tax extension request do no have to be accurate, except for the amount you are paying, if you make a payment with your extension.  Even if you will owe tax, just use numbers that result in a zero tax due if not making a payment or that result in the amount of the payment amount if you are making one.