What nerve ...

If the carpet got wet, you need to lift it up and examine the condition of the carpet, pad and subfloor. 

Make sure you have a reputable septic company go out and give it a thorough examination prior to closing.

Get a state Realtor's examination book and read it understanding each chapter, you can skim the RE commission stuff but be aware who they are.

Very nerve wracking.

Examine the septic system for flooding or unusual odor.?

The only caveat I'm going to throw in there (having been a Surplus Lines Claims Examiner for many years); if it's a commercial policy (which we are assuming it is), rest assured they will be doing an extensive investigation in the matter, specifically because the limits are likely significant.

Be sure to use a good title company and make sure the purchase agreement is examined by a professional that can attest that everything is in order.

Excited for this new venture and can't wait to get started, but I am already feeling the nerves!

I've kind of been going by "gut feel", but as the market appears to be slowing it's obvious I need to review more data.I will more closely examine all the items you mentioned.