Regardless of the setting of "Keyboard HUD Icons", the ones attached to the crosshair ...crosscircle ...circlehair can not be disabled.
The "Assign" HUD Icon on an empty hotbar slot is also displayed for all values.
At least for a player familiar with the game, this may be unnecessary, annoying, or distracting. If this is actually working as intended and 'None' actually is meant to mean 'Still a few', then please consider adding another step that really means 'None AT ALL'.
For the hotbar icon, it wouldn't be as jarring if it would behave like the regular hotbar labels do - either have it time out, or have them not time out. 'None at all' would still be the preferred option.