It is late and there are a bunch of links to read on this thread (thanks to the posters) YET it is late and these things will work themselves out–well I guess by greater minds than I will at least.
An odd thing I found, with rbp2 b+ & "VERSION_ID=“2016.02-1"” of OSMC, is that with Confluence skin at least, that I could us the “i” menu and the trailer button without fail… but the search says “BAD Request”–who is YouTube to judge my search for “Afroman Because I Got H—”?? hehe
Kidding, 
but the APIs for the addon I assumed were same for both commands (text search and the “trailer” rectangle on “i” screen), but I leave it up to you pros & Kodi team 
Afroman will bumpbump in due time. So in my words the current state of the YouTube addon would be something like…
“It [YouTube addon] runs, but not on all four cylinders ATM”
Thanks to OSMC/Kodi team for keeping my lil’ SoC cruising. 