Apologies for my delay in replying.
1. Is there a fixed assignment of keyb and mouse? How is this handled as PS/2 uses different pins/signals for keyb vs. mouse.
Current firmware is fixed, but all data pins of the PS/2 connectors are wired up so it will be flexible. In fact I plan to allow combined Keyboard/Mouse output from one port for dual-use PS/2 inputs (like on some laptops)
2. What about wireless desktops where one USB receiver handles both HID?
They work great, I recommend their use
![Smiley :)](https://www.eevblog.com/forum/Smileys/default/smiley.gif)
3. Did you source your chips from LCSC?
I've bought them in various places (ebay, aliexpress). Never come across a broken one.