Thanks for making such amazing turn-based rpg! We need more turn-based rpg!
I am currently playing the linux version (which play perfectly on my linux mint OS).
I will post here my thoughts when I finish game.
FYI: to open all the panels I am using TAB and select from the menu the panel I need. At least for me, the combination of TAB and arrow keys (which are also used for movement, enemy selection, etc) feels better than using the other shortcuts.
Using the above control scheme I think 1,2,3,... feel better for character selection.
In any case if input rebinding is on your to-do list we can always change the keys from our end.