I have been able to rub the pinholes out at greenware. Depending on what your mold looks like will depend on if your piece will crack. How many pieces is your mold? Is it mostly enclosed or have a large open area? I have had some luck on a 3 piece mold taking one side and the bottom off, leaving the other side horizontal with the piece still inside of it. Then putting the first side back on and flipping it and exposing the wetter side to air.
You can reclaim the botched and dried pieces - takes time, but it can be done.
It takes practice and time to make good slipware. Good luck
For human urns I've been told to figure 1 cubic inch per pound. For a 200 lb person + or - that would be an inside measurement of 6 x 6 x 6. I've figured that to be a bit less than a gallon size. For Thanatos at 10 lbs that would be less than 3 x 3 x 1.5, maybe a cup, cup and a half. You do beautiful work. I'm sure Thanatos would love being always near you as you play in clay.