inkBot - unfortunately which controllers are supported depends entirely on the browser - we can't do anything to add support. Browser makers are still working on it though, so I anticipate it will improve gradually over time.
Good point about the missing triggers - added to the todo list.
You can either use global variables or a third party function plugin (official features will be coming soon) to handle control input. Alternatively the events you gave can be rewritten easily using a subevent:
Left arrow down
OR
D Pad left down
---- Player on ground (subevent)
---- Do stuff!