Exactly what I needed. Thank you, Mr. math.

if you have a desktop shortcut to LH, copy the default shortcut, right click the copy, select Properties from the context menu (bottom of the menu); on the "Shortcut" tab, add " -cheat" to the textbox labelled as "Target:"

full path in the textbox should be something like: 

"C:\Program Files (x86)\Steam\steamapps\common\FE Legendary Heroes\LegendaryHeroes.exe" -cheat 

close the dialog with OK, after that, the copy of the shortcut will start the game in "cheat mode" which enables the key combinations parrot posted.

EDIT: you don't actually have to make a copy of the shortcut - that's just a convenient way of having the option to run the game normally or in cheat mode

Thanks guys.