"They aren't hard to get into for any applicants" is just wrong, as times have changed significantly. Whenever I was thinking about ENT as a young medical student, H&N wasn't an attractive fellowship due to patient characteristics, work volume, hours, pay, etc. However, over the last 8 years it's been significantly revived as a specialty and is now again drawing the best residents from allopathic ENT programs. With the advances in free flaps, TORS, and endoscopic anterior skull base surgery over the past 10 years, H&N is back as one of the most popular fellowships. Last year, for the first time I believe, there were more applicants than fellowship spots, and those applicants who didn't match weren't lacking in credentials.
I think the days of Gen Surg applicants going into H&N are numbered unless they come from a big academic program with heavy research or a program that does lots of H&N. The fellowship directors will explicitly tell you that the purpose of fellowship is not for honing your skills in neck dissections, thyroids, parotids, laryngectomies, etc. The fellowships are intended to gain competency in free flaps, skull base, robotics, and the most complex extirpative procedures. I don't think they'd be patient with a fellow coming in who's never held an endoscope in the nose, who logged 3 parotids in 5 years of residency, who has never worked on the face, etc.
As for job prospects for H&N without ENT board certification, that's also difficult. H&N jobs are primarily going to be at bigger academic institutions. You can't take ENT call if you aren't ENT trained. If you can't take ENT call, then your value to the H&N division in an ENT department is meaningless; no one wants to hire a young surgeon who can't help in their call pool.
Don't mean to bust your bubble, but you're fighting an uphill battle.