You can buy fuse through the mail. I use
CannonFuse.com(I'm assuming you are in the U.S.A.)
They ship fast but fuse can be sent via surface mail only, so expect to wait about a week for shipping.
There are some board sponsors that make ball molds. You can find them in the stickies at the top of the page.
I bought the 1.125" mold that I use for my ¼-scale Napoleon from J-T Moulds in the U.K., but that was a few years ago and I'm not sure if he is still making molds.
(Those handles are for a six-cavity bullet mold.)
If you can figure out which weight you need, cannonball sinkers can be often be used as projectiles.
If you do find a size that works, sinker molds are cheaper than dedicated ball molds. But you will want to make a ball gauge and check each one for roundness. Inexpensive sinker molds can't reproduce the quality of a good ball mold.
My handgonne is only a .50, but there are other members here that have gonnes up to golfball caliber.
I need a bigger gonne (and a smaller one).