Hell all! Is there a keyboard shortcut to change a path stroke Line Cap from the default Butt Cap to Round Cap? I can't find anything on that. If not, it is possible to create a shortcut? I can't seem to make that work.
No. For such rarely used functions it wouldn't make the most sense to begin with and due to how AE works there are serious limitations in what can be assigned to a shortcut, anyway. At best you could create a script and assign it to a button or shortcut, but off hand I'm not even sure if the pop-ups are accessible in a way that would work.