I agree they are confusing, however as there is not documentation and videos on the subject I’m not radically going to change that. Perhaps on the next major release/update.
As I mentioned, its just a header, not mandatory.
What are people needing 8 relays for? What is driven through these?
The INA chips are fine, but again there are multiple variants of those depending on voltage measurement needed - do we install 48V or 36V etc. a daughter card would be useful in this scenario.
Likewise, should a change in measuring tech be needed in the future, the daughter card can be swapped out/upgraded without replacing the whole controller module/pcb.
You’ve still not mentioned how you are keeping the high voltage isolated from the 3.3v circuits.