First of all I enjoyed your nice translation back into English of the Japanese version of the song. As to the question you raised in the second line, perhaps I can help.

“Mugi” is “barley” or “wheat” and “mugihono” is a “head of wheat” (when the grains of wheat are all still stuck on the stalk and have long spikes on them and hence are bearded or unharvested. Technically barley is “Omugi” but not that many Japanese (or non-Japanese) are that sensible of the difference anymore. This ends up being a wry “comin through the rye” imagery that I am pretty sure was intended in the English at least) “hotori” in this case means boundary or vicinity and for this purpose boundary is best. The best retranslation back into English would be “Kiss me beside the bearded barley”. The English is “out of” but in any case (back to the “comin through the rye song” “out of” suggests “at the boundary” and one is lucky if one can get the Japanese and English to match that much of the time (other places the specific meaning of phrases appears to have changed more to appeal to a Japanese listeners aesthetic sense and to keep the beat going-as your very nice translation back to English clearly shows). Other than what I presume was a cheerful nod at the old Scottish folksong I mentioned, I doubt the writer was trying to burden the song with very much in the way of hidden symbolism (whimsy, maybe). I think the song is entirely what it appears to be both in English and Japanese and I am sure that will not disappoint anyone.

Best Regards

GELoy