Is freeze-dried raw safer than fresh raw?

Not meaningfully -- freeze-drying does not reliably eliminate bacterial pathogens the way cooking does, so similar food-safety precautions apply to both.

Do I need to add water to freeze-dried raw food?

Many products are designed to be rehydrated before serving; check the specific product's instructions, since this affects both palatability and, for some formulations, how the nutrients are intended to be delivered.

Is freeze-dried raw more expensive than fresh raw?

Generally yes -- the freeze-drying process adds cost, making it typically the more expensive of the two raw feeding formats per calorie delivered.

Freeze-Dried Raw vs. Fresh Raw Pet Food: What's the Difference? | PetCalculator

Freeze-dried and fresh raw diets share the same "raw" label but differ meaningfully in safety, convenience, and cost. Here is how they actually compare.