Why are my facets not showing choices for all my products?
The most common reason is that you are showing out-of-stock products on your products page, which is default WooCommerce behavior (which can be changed with a setting).
However, FacetWP does not index out-of-stock products by default. You can make FacetWP index them by enabling the “Index out-of-stock products” setting under FacetWP > Settings > Woocommerce.
After enabling this setting, make sure to re‑index.