I can answer this with some degree of accuracy, and I think the above is fairly accurate.
So to begin with, you have ENT, ENT facial plastics, and then there are some ENT reconstructive fellowships. You can also complete an ENT residency and then go right on to do a full PRS fellowship (I wouldn't, but I know people who have).
General ENTs can do facial plastics. Most of us do at least some of these procedures - at the least some local reconstructive flaps for skin cancer defects, and in many cases rhinoplasties, facelifts, etc. You don't have to do additional training, you just have to be comfortable doing these things. We all do them in residency, just to varying degrees.
Craniosynostoses is tough to break in to with ENT. You can, certainly. But it tends to be dominated by PRS (usually a general surgeon who went on to a plastics and reconstructive fellowship, but really anyone who completed a plastics and reconstructive surgery fellowship). So even if you're trained to do it as an ENT, you might have trouble finding a job where you can just start doing those kinds of procedures. You might find someplace to train, but unless you get a job working at the same place, you have to go find one somewhere else, and that might be hard. There's a bit of territorialism in that sort of thing, and as mentioned above it's almost exclusively employed or academic in nature. In theory, you could open a practice and build it up doing craniosynostoses, but that is usually going to be a huge uphill battle that you will supplement by doing a lot of more general ENT and plastics.
ENT does a ton of skull base reconstruction, which is a whole other animal to include: skull base sinonasal tumors, temporal bone tumors, post traumatic skull base reconstruction, etc., etc., etc. Usually these are in conjunction with a neurosurgeon, but skull base recon is pretty solidly ENT.
Cleft palates - These are fairly well divided between ENT and PRS, and very regionally dependent as to who does them. I think you can probably do clefts using either route, it'll just depend upon where you go as to whether you can just walk in and start doing them, or whether you'll have to build a practice. Frankly, for soft palate and lip clefts as well as cleft lip rhinoplasty, I don't think I would have needed a fellowship to do them. They're not THAT complicated, but you have to have experience with them of course. You'll definitely be a more competitive applicant (and more attractive to the extremely nervous parents) if you have a fellowship. With ENT that might mean facial plastics or it might mean pediatric ENT.
There are actually some published articles out there looking at who does more of what (ENT vs. PRS) for common facial plastic procedures, and none of them break down the way you might think that they would. ENT actually does more cosmetic rhinoplasty than PRS, but PRS does more otoplasty (which seems odd to me, but that was what one article said). Nonetheless, I don't think any of that matters, because you can tailor your practice however you'd like.
So here's what I would say (sorry for any repetition)
Most ENT facial plastics guys don't actually do a lot of facial plastics, but that is entirely by choice. They just wanted the fellowship to look more attractive for the job market. You don't need to do a facial plastics fellowship as an ENT to do most facial plastics procedures, but the additional training gives you more exposure and if you want to do free flaps, well then you need the fellowship.
A lot of PRS guys don't do any cosmetics either. Just depends upon how they focus their practice. Some do only hand, for example. Others have entirely cosmetic practices that include facial cosmetic procedures of all varieties.
As an ENT facial plastics guy, you can do face lifts, brow lifts, rhinoplasty, otoplasty, facial fractures and trauma, clefts, auricular reconstruction, free flaps, facial reanimation, facial transplants (if you really want to be ultra-specialized and spend most of your time not doing your primary thing just because it's extremely rare). You can do almost anything above the clavicle that doesn't involve working inside the dura, spinal cord, or eyeball. Same as the PRS guy, you can do basically anything. You're just not doing boob jobs or tummy tucks. You can work for a hospital, or you can work for a university, or you can be privately employed. The bigger issue will be what you can do in each of those situations, because (for example) most cleft work is going to be done in a hospital or university setting. You really need a multidisciplinary clinic to manage those cases well, and that's just too cumbersome for most private practices.
If you do PRS, you can specialize in facial and craniofacial surgery. That, again, depends upon where you train and what you want to specialize in doing. This isn't additional training so much as it is just spending more time doing cosmetic facial surgery (for example) during their fellowship.
Here's what I've always said (and this is meant to be facetious and unfair): If you are a patient looking for a plastic surgeon: you can either go to the guy who spent three years working on colons, and then another three years split between cosmetics, craniofacial, hand surgery, boob jobs, and closing gaping wounds in the crotch, or you can go to someone who spent 5 years working on the head and neck and facial plastic and reconstruction and then another year working on nothing but facial cosmetics and reconstruction. Your choice.
But the truth is, you can do these things via either path. You might consider the route through that training rather than the end point. Meaning, if you wanted to do, say, facial cosmetic surgery - you can do it either way. So do you want to do a 5 year ENT residency complete with sinus surgery, ear surgery, tonsillectomies, and head and neck cancer as well as facial plastics - and then a facial plastics fellowship? Or do you want to do 3 years of general surgery, or an integrated PRS residency where you have to develop skills as a general surgeon and work on hands, etc.? If you're going to lose your mind doing tonsillectomies, then that will answer your question.
A final point:
It might actually be easier to find work as an ENT in a private practice setting. Maybe I'm off base on this, and you'd have to verify from a PRS guy. But my thought process is that most ENTs can literally just rent a space, buy equipment, and set up shop almost anywhere as long as the market isn't saturated. You usually have to build up a cosmetics practice, and in the interem you have to subsidize your practice somehow. If you're an ENT, you can very easily subsidize with fairly uncomplicated, low risk general ENT as you build the private cosmetics practice. This is a very common situation for ENT-facial plastics surgeons who ultimately only want to do cosmetics.
