And thats of course disregarding the time spent in class and studying for the exam and putting the pressure on yourself to properly know the ins and outs of the contract since you will be representing yourself. 

be sure you have proper insuranceEnjoy being a landlord! 

So, if the sheetrock is up, and you plan to pull permits now there's a good chance you will have to tear it all off so the inspector can properly inspect the framing and insulation. 

@Nick TalaricoAs suggested - it helps to have a separate bank account for just your real estate related activities.This way you know 100% of the activities within the account are related to the real estate related activities.You can export the information into excel and properly categorize the information.One you scale up, you may want to consider having an accounting software such as quickbooks, Stessa, Quicken, etc.

House was poorly configured with multiple additions and never properly laid out.

You will already have made money "purchasing" it, so your initial capital at risk is $0, just added liability and future major costs, which are likely mitigated by builder warranties and proper insurance.Make sure you have all numbers correctly considered, do your due diligence and ask yourself what the worse case scenario is. 

Find out when he's home and stop by-bring another family member along.I know you've sold it, but for future reference, you don't need his permission to enter, you just need to give him the proper notice-usually 24 hours.

Learn how rentals work with this first investment, DIY as much of your own maintenance and property management as you feel comfortable with, get your feet properly wet and your hands property dirty. 

If you have not established the proper relationship with them or they don't have anything to authenticate or verify you yet, an email is not worth anything.

I agree with the others that it is the end result (i.e. does it look right and function properly) that matters most, not so much a piece of paper.