Been muddling along with snippets of learned and assumed Gaelic from Scots and Irish sources for several decades now. I'll say, as many of you have found, that being able to connect the sense of a song with yourself and ultimately with your audience is the most important thing.
In performing or teaching, I find that people will happily sing along with repetetive choruses in a strange language (or even in "scat"!), but they get more involved with a song if they can follow the story.
My main concern in folk-singing lies in sharing the meaning and the mood, and my main audiences are English-speaking.
Though I surprised a few friends and tutors when I translated Gaelic verses into Beurla when our trio recorded several traditional songs, that decision was consistent with making the beauty accessible to other who might not otherwise find it. But I also encourage people to go on to learn more of a song's language and culture, which some of my students and fans have done.
One of my favorite teachers, Gaelic scholar Dr. James (Seumas) Duran, has been known to show people the many ways in which different Gaelic dialects would express the same phrase or idea. There are even dialect differences based on the *gender* of the speaker. So the discussion of "correct" intontation and phrasing may be much like a discussion of the "correct" recipe for stew.
Work with what you have, be honest, be open, learn, share, collect, enjoy. Expert opinions are, after all, just opinions.