A guy/girl from HD is NOT the person to give you an accurate renovation cost/budget.

Appraisal $2500 seems accurate, you should get an engineer inspection $1000-1500, I personally would but this is optional if the building appears to be in good shape..

Is this accurate?

Is there a method to accurately predict arv accurately without having to leverage your own years of experience?

You'll get the most accurate advice and guidance from someone who walks the walk, not just talks the talk.

Consumer self reported scores are generally accurate on the very high end (790 reported v 820 actual = same interest rate pricing, no difference), and very accurate the very low end (480 reported v 498 actual = no Agency mortgage either way). 

@Michael Woodruff I'm completely new, in the total sense of the word, but what Abel said was 100% accurate....

This is pretty complicated and in order to get even close to an accurate answer your question, you'll need to provide the filing/recording dates of the mortgage/deed of trust as well as the FTLs.

You're not gonna get an accurate price online by just saying the sq footage.

The question is the return accurate?