To my surprise I do see a melodic resemblance between 'Donald Where's Yer Troosers' and 'Séarlas Óg', even though the tempo and whole ambience are miles apart! I found 'Lucky Wee Prince Charlie' on Tobar an Dualchais, and the tune there is exactly the same one as used in Ireland with the de-Jacobitised lyrics. That suggests to me that Blythman may have got it from there, but he was obviously also aware of the Jacobite associations. I would really like to find that Kitty MacLeod Gaelic recording.