It's an interesting theory but I do worry a bit about 'over fitting', where everything must have a complex lore explanation.

Go outside and walk down the street. Some women have earrings. Some don't. Is there some secret code to this? No, not really. It's mostly personal choice. Oh we can take some signals from earrings and their lack. Social class, subculture etc. But these are soft signals that will be wrong as they are right.

I'd suspect headskirts are similar. They're a fashion choice that some wear and so don't. It might hit at subculture but I think it's something more arcane than 'top dog'.

I think the saucer separation ability was an example of theoretical thinking. The Galaxy class designers clearly intended a use for it. In dangerous times, the saucer would separate leaving the stardrive section free to act without it.

But, via practical real world experience, Starfleet learned that separating the saucer section was seldom worth it. It was too slow, where danger tends to occurred suddenly, and, even when there was extra time, Galaxy captains learnt the extra power generation of the saucer proved more useful than the decrease in mass. I doubt the War Galaxys from the Dominion War even had the ability and, if they did, it was only because it would take too much work to remove.

It's possible that the saucer section worked better as a one-use 'super-lifepod' but the original plan of combining and transforming ships clearly didn't pan out. Same thing seems to have happened with the Prometheus with Starfleet deciding the 'wolf pack' attack mode innovations, while effective, are better implemented via separate ships. Like we see a trio of Texas class ships doing to take down a Sovereign.

(There's clearly some guy in the Starfleet bureau of ship design who keeps trying to make combining/separating ships happen and keeps getting disappointed when they don't pan out in practice.)

The decision in Una’s case, to treat each case on its on merits, also provides us with a reason why the only issue with Dal in PRO was whether he be allowed to join the Academy, not his mere existence as an Augment in the Federation as the kids were all fleeing Tars Lemora.

I don't believe the refugee exception is necessary to explain that.

As we see in this very episode, it's not illegal for a federation citizen to be genetically engineered. Under the rejected plea deal, Una would have been kicked out of Starfleet but kept her citizenship. They are prohibited from certain professions (Starfleet being the main one) but it isn't illegal in and of itself.

The Federation wants as few such people as possible (see the bans and refusing large groups of augments entry into the Federation) and it's illegal to perform or cause modifications to be performed, but just being augmented isn't in and of itself a crime. Notice how the charges against Una were chiefly about her lying to Starfleet and the deceptions stemming from that, not just being an augment full stop.

This is even more clear with the Julian Bashir case a century later, where, again, it was the entry into starfleet that was the problem. Just being an augment wasn't a crime in and of itself.

To sum up, assuming Dal could claim citizenship in the first place, being an augment wouldn't be a crime in and of itself, though he would be barred from certain occupations.

It is generally taken for granted that a similar rule or law must be in force for Federation civilians.

There's been a lot of arguments on this point over the years but I stumbled across a pretty clear answer on this point.

BASHIR: You're going to make a move against Koval, aren't you? You're going to find a way to use his illness to keep him off the Committee. I suppose it would be naive of me to point out that interfering in the internal affairs of a sovereign power is explicitly forbidden by the Federation charter.

http://www.chakoteya.net/DS9/542.htm

Interfering in the internal affairs of other species is, of course, the crux of the prime directive. So, yes, not only is it banned at the Federation rather than just the Starfleet level, it's written into the Federation's constitution itself.