how create hotkey for focus the opus (minimize and maximize from the tray)
Perhaps this is what you are looking for: [Minimize/Restore)
Some extra info: You can't minimize Listers to the Taskbar Status Area (tray) as far as I know, but I use a freeware utility called WinRoll (very low on resources) to do this. It doesn't support hotkeys, but it lets you click the minimize button with your middle mouse button to minimize a Window to the Taskbar Status Area. Link: http://www.palma.com.au/winroll/.
If there's only one lister then you could set Opus to remember the state of the last lister and then simply close the lister. Then when you double-click the tray icon to open a lister it will re-create what you had before. Pretty much the same as minimizing to the tray.
For more than one lister it's a bit more complex. Opus can automatically remember multiple listers when you shutdown and re-create them when you restart, but that doesn't get you a tray icon. You could, however, create a button which saves the open listers to a Layout and then closes them all. And then configure the tray icon double-click to open the same layout.
Those still require two buttons and don't give you a one-button toggle. To do that I think you would need to have something which checks to see if any Opus windows are open and then launches one command or the other depending on if there are. You could do that using AutoIt or AutoHotkey, I guess.