Where can I buy plaster molds?

I would guess that you can't. I take your question to mean that you want to buy hollow forms (molds) to pour plaster of Paris into to make the things you name so you can sell them. Not very popular right now as a hobby so the ones selling the plaster stuff have made their own molds.

On the other hand, if you meant you want to buy the cured plaster things - they are heavy and fragile and still not very popular so you will have to hunt locally, where ever that might be. These days most of the Christian decorative items are likely to be plastic or resin - much less breakable.

I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.