I have a few catas that would be nice to brew if I have time, I have been considering buying another cauldron or two to do so but I don't quite know when the fest ends/brewing ends. What happens if I don't finish brewing a pet?

Access to brewing doesn't close until Sunday, December 6th at 11:59 PM, as stated in the overview, so yes, you do have time to finsih them

At that time, most unfinished pets will be lost to the void, though exceptions may be made for pets that have over a certain percentage completion + blood added. Those pets will be placed in the hatchery when Krin gets to it

Yay okay thank you! : )

edited our last post because we missed the last bit of the question

Gotcha thanks so much! ^-^

Quick update on the date when the remaining fest features end. A day or so ago, Krinadon announced it would be extended to the 9th, since the prizes from some of the fest games & contests were catas (as was the first non-premium advent calendar prize).