Maya's Hotkey Editor is pretty robust, you should be able to do everything in there (Window > Settings/Preferences > Hotkey Editor). If by "toggle selection" you mean to switch between object and component mode, I think the code is SelectToggleMode That will switch between object mode and the last active component mode.…
Ctrl+RMB, Ctrl+Shift+RMB, Shift+RMB. The triforce of Maya marking menus. For a lot of hard-surface modeling tasks these are almost all that you will use, barring custom tools. These, however, are context-sensitive and will change depending on where your cursor is over and what selection mode or tool you are in. As for…