EDIT: a case of mistaken identity, please ignore.
shift+ right-click on a word to get a definition. I was actually trying to invoke that software from Logos when to my great surprise, a dictionary opened in Logos as well
For me, Shift-Right Click opened the Logos right click menu. Did I miss something in your post?
Cmd-Right Click (Mac) opened the Information panel.
Same here...so it could be different for Mac.
FWIW, double-clicking a word opens the dictionary for me.
Well, well, it would appear that this behaviour is not actually native to Logos but is caused by the other software (lingoclick). I verified that by turning it off.
False alarm then, sorry.