Q:

How are acceptable audit answers decided? 

I stumbled across this question while reviewing first posts.  It essentially has 2 parts, how to organize client-side user authentication code the Redux way and how to best integrate Facebook login into Redux.  I flagged this as "low quality" since the first part should be a simple Google search and the second part is asking for opinion-based answers.  However, I failed the audit because the question was "high quality". 
So, my question is: how are the answers for these audits chosen?  While flagging this as "low quality" may not have been the best solution in this situation, I feel that marking a question such as this as "high quality" is a little over the top. 

A:

Audits are calculated by the system based on the queue in which they occur. 
Suggested edit audits are computer-generated gibberish, sourced from anonymous users.  Under no circumstances should anyone approve those, and if you do, you deserve a little time off from reviewing. 
First Posts (the one you failed) and Late Answer reviews both have positive and negative audit cases to prevent people from both blindly upvoting and blindly downvoting posts.  For one set of audits, open posts that are highly voted are used.  If you downvote those, vote to delete, or try to flag them, you fail the audit.  On the other side, deleted posts with accepted "not an answer", "very low quality", or spam / offensive flags are used as audits.  If you vote "No Action Needed" or upvote those, you fail the audit. 
Likewise, the close vote queue has audits that are determined based on open and highly voted questions.  If you vote to close those, you fail the audit. 
Due to that fact that questionable posts sometimes get upvoted disproportionately (from voting rings, exposure due to bounties, different treatment of questions in different tags, or changing standards of what's acceptable here), you'll occasionally hit problematic audit cases in the last three queues.  These audits are needed to combat review abuse (which would be rampant without them), and truly bad audits tend to be relatively rare, but it would be nice to have a mechanism to remove them from circulation. 
All that said, flagging that question as "very low quality" was incorrect.  That flag should only be used for absolute trash that must be removed immediately.  If the question is merely too broad or opinionated, cast a standard close vote or close flag for it. 
Personally, I think we've got a lot worse things to worry about than a question like that which was well-received and seems to be getting good answers, and I wouldn't vote to close it myself.