No grinder, Can I use a food processor?

I currently do not own a grinder, is it ok if I use a food processor in the meantime? I crush up the bones with a hammer and process it by itself, than I throw in all the meats than mix the water/vita slurry

Yes, that is fine.

You could also omit the bones and add powdered eggshell instead. That would be less likely to damage your food processor. You need 1/32 tsp. per ounce of muscle meat and 3/tsp. per ounce of organs. All you need to do is wash the eggshells, let them dry (the oven would work well), and grind them in a coffee grinder or even the food processor.

You can use a food processor. Here is one way to grind meat: http://www.thekitchn.com/how-to-grind-your-own-meat-in-134272