Moving notification buttons in settings

Hello everyone! I am new here, this is my first post. I didn"t see any post about this.

In settings, display, notification bar - it says I can move buttons off bar I do not want into the "Available buttons" area. I have tried to do so, and it says "maximum number of buttons has been reached". In the available button area there is one button, with at least 6 empty spots. Why can I not move buttons I don't want because I don't use them? Plus, in the list of buttons I can move around in settings, it doesn't show the "mute" button which is on the notification bar. Why is this?
Another question: I have a bluetooth keyboard that is paired with the tablet, and I have it marked as default, but when I tap on an area to type, the viritual keyboard keeps popping up. Is there a way to stop this as well?
Thanks for any help .