Hi there,
1. Yes, GenerateBlocks is developed by us.
2. No, this will have to impact on the development cycle of GeneratePress & GeneratePress Premium.
3. Pricing and discounting is still under review at this time.
The two plugins are intrinsically different, GPP is for theme level controls, whereas GB is for Content editing. We have always maintained that a Theme should not command a users content so the user is never locked in to the theme. The only area where GB replaces anything theme related would be the old Sections Module, which is now redundant for any user working with the Block Editor.
If anything our development of GB will only enhance the development of GP + GPP. With advancements in WordPress moving towards more React.js over PHP we will be ahead of the game if the Theme has to update to this technology.