As of right now, a lot of the FSE features are still experimental. We won’t be making any major decisions until things are 100% solid on the WordPress end of things.
As things become more solid and make sense to merge with GeneratePress, we will definitely do so. I don’t believe GeneratePress will ever be 100% block-based, but I don’t see why we can’t make it even better as time goes on (a lot of the features in FSE are already possible using Block Elements).
Yes, we will continue to improve our WooCommerce module in the next few versions.