What is up with pad/pin numbers for those symbols?
The pin numbers (be they letters or numbers) need to match the pins in symbols AND in the footprints.
If you got a connector with 3 pins and the symbol has got ‘GND’ as pin number the footprint will also need a pin with that number. But this will cause havoc and proprietary among your footprints… stick with numbers for pin numbers, so you can REUSE footprints and symbols.
I think (with what little I know of this) you’re treating the system wrong.
If you want nets with names like ‘GND’ you either have to use the pin/pad name field or add labels (local, global or hierarchical) to the nets (wires) in eeschema…
The way you do it now is wrong IMHO.
Who made those symbols?