MY ultimate goal, if possible, is to have Multi Commander always open to the specified paths, with a Folder Tree pane open for each, and with the left Explorer Pane having focus.
If you launch MC with the command line params, you can specify User Defined Command.
MC.SetActivePanel PANEL=LEFTThis activates left panel.
MC.RunCmd ID="ExplorerPanel.41070"This toggles a panel tree. Each panel has its own tree, so it is possible to have some tabs with trees and some -- without.
In the Explorer Panel settings there's an option Display > Tab > Default Settings for new tabs > Show folder tree. So you may open desired tabs, then activate left panel on startup via command line and UDC.
You can get a lot of info in the official online documentation.