Not sure if a general icon reflects what exactly you have to do to toggle things. Or was your plan to make it show a menu? Not sure if that's a good idea...
On my laptop, brightness toggles are on the right (Fn+arrow up/down for display brightness, Fn+arrow right for keyboard backlight (cycles between 5 steps)).
"Press F-ing Q for help!"
Yep, sounds legit...
Can't find much more to improve in my proposal. Suggestions are welcome.
http://www.keyboard-layout-editor.com/#/layouts/31c8ee9b342fe57cc4fd356c47e1d3e9
Suggestion for a 4 way key swap:
Put Insert where + is now.
Put Delete where - is now.
Put + and shift - where Enter is now.
Put Enter where Delete is now.
Logic/reasons for above multi way swap:
Currently Delete is where most users would expect to find Enter (one down from BS).
Any confusion between Enter (launch program) and Delete (delete icon/program/file) should be avoided when possible.
Insert and Delete logically and historically belong with page up, page down, home and end.
Having + and - share a key with shift to make - simply makes sense.
Enter simply 'feels more right' to have directly under Backspace on the upper right side.
If Enter must be on a dedicated key, move F12 to where Insert is now.
IMHO - it's your layout and you asked for opinions.