You can open a new terminal by middle clicking or by pressing ctrl-leftclick.
The following CPU-monitor is quite good https://extensions.gnome.org/extension/120/system-monitor/
Regarding fixed layout I would like to have an extension that allowed me to press a button, and have gnome-shell rearrange all the windows for me.
I personally never liked the upper left corner, so I use the axe menu. My only problem is that the axe menu does not allow me to arrange desktops. (I miss the old gnome 2 desktop applet) https://extensions.gnome.org/extension/327/axe-menu/
But my biggest problem is that gnome-shell is unstable. These days it freezes daily, so I have to open a terminal and write "gnome-shell --display=:0 --replace &". In the past I have had problems with extensions that suddenly caused everything to freeze after an update, but this time I cannot guess what is wrong.