Hello!
After reading your comment, I detailed in the book that the timing of level-ups and the passing of time are up for the Master of the Web to decide, as they feel is right for their game.
It's very important to me that the passing of time could feel random or arbitrary, as children's understanding of time is unclear and variable. I find it's more interesting to rely on personal assessment than on a rigid system, as it can surprise players or support an atmosphere. It was only implied, but your comment made me realise it was important to clearly say something about it in the book. I have been very lenient on these rules because I want to leave room for interpretation: if it's not mentioned in the rules, follow your inspiration and stick to your adventure's atmosphere! I could have forgotten something more structural, though, so thank you for your constructive remark.
As to food production… Early on, when I was creating this world bit by bit (and I still am!), I wondered about it, before I put it off for later. It now seems a level of detail unfit for the first book, hard to explain without it taking up too much space compared to the rest. It's important, but not as essential, and not something I want to emphasize.
However, I'm glad you asked about it, because the answer dawned on me. I now have an idea of the city's sources of supply that I could expand on, probably in an adventure for Night Fable!