There are some portraits I think are so bad, I may ask the  people if they want a private session time without the insanity.  
I did not do the scheduling, the charity did.  I voiced my feelings on the matter and they said there would be plenty of help.  The volunteers tried their best, but, I am used to a much lower stress, all the time in the world time. 6 minutes is not enough.  Not for me at least
Very very  few people wanted to be in the photos with their pets. It was much easier when they were.  
I enjoy a more interactive candid style portraiture, but that is not what people came to this for. They wanted pictures of their pets.  I did *many* things wrong.  Flat lighting was the least of them.  I can forgive myself for that.  
I have a long ways to go before being "good".  I was mostly proficient this weekend. Well, Saturday and Sunday. Friday I was just bad