I thought it was a clever way to handle it, but it was... strange because it telegraphed it's narrative purpose rather than keeping it as part of the narrative. But I mean - to be fair I can't think of a better way to make it work than exactly what they did and I thought it kind of worked out well all things considered.
Pursuant to this and maintaining consistency with the CO/XO dynamic on many Starships it's totally reasonable to have a small vessel commanded by a Lt. Cdr. who we call the Captain, with a Lieutenant as the first officer.
We do not know when the UEF was formed. It could be a relatively new initiative having taken longer to get started without the help of the Vulcans. The USS Iowa is a United States Starship whereas the UEF Enterprise is the United Earth Fleet ship. Sometime between Kirk's birth and the 'present' Earth was finally able to form a central government (or at least a centrally organized spacefleet) under one banner.
I think narratively it's just a much more enjoyable to not have Odo shift shape onscreen, especially as it gives him the ability to overpower a lot of people. In the early episodes this needed to be shown so we could understand Odo's character, but by the fourth season (both when he was a solid and not) we knew enough about the Changelings that we didn't need to show this as frequently and had to figure out more creative ways to to get around Odo.
Yes this is likely a consideration, but I also wonder if the ability for humans to live both without interference and in harmony with natural surroundings is now taken as a given such that no one is expecting anyone to deface or damage the redwoods even if they had set up their camp there to complete their research.
I would really like to see a series which focused on establishing a colony and the specific challenges that settlers face. There are probably a lot of interactions between civilian Federation organizations, civilian individuals, colonial governments, and Starfleet. I think there's a lot to explore here.
I think we can also say that Starfleet (or the Federation) is better while still allowing the stories to be allegorical and topical. I mean, it was unfair that Richard Bashir went to jail for genetic tampering because it's a bad law, but 2 years on in a Federation prison is just not quite the same as what we have now.
But, to that end, Starfleet has always looked a little bit like this. They tried to treat Data as property. They tried to do racism against Crewman Tarses. And imperfect officers break the rules and sometimes forge evidence to sway a Romulan senator - or murder them.
Allowing for that nuance is interesting - and holding Starfleet to a higher standard also lets us understand where we as regular people need to be held to higher standards. I would love to break canon by doing prison abolition before global catastrophe.
You are correct. We can't really infer much about Una's citizenship status and so letters of recommendation or sponsorships aren't of concern. But with that being said - if Una can be a citizen and be modified then so could Dal. Albeit the restriction on genetically modified people serving in Starfleet seems to stick all the way through to the late 2370s and early 2380s at least.
In fact, unfortunately, we still see a fair amount of bigotry towards modified people persisting into the 2370s, but perhaps by then the difference between a modified Ilyrian and a modified human are more substantial. Dal, being a non-human (I guess?) might face less bigotry in his era than Una faced in hers.
That post is actually what made me consider how well Discovery managed to do what the OP mentions in their first season. Answering the question of "why send all the senior staff" by making the main players not senior staff just works.
I think this can quite easily be pulled off. Lower Decks is an example of this to a degree, but for an even better Beta Canon example look at the Star Trek Resurgence narrative game. The story takes place from two perspectives Petty Officer and the ship's First Officer. Each of these characters has relationships which will impact the story and for the most part they work separately from one another, but still work together and it makes a lot more sense when the Captain sends the Petty Officers to go on the hull and do dangerous work than sending the chief of any department.
Consider that Deep Space 9's primary cast of characters includes an enlisted person and several non-Starfleet personnel or straight up civilians. Porting that to a TV show would not be that difficult and I think there has even been some success with that in Lower Decks which features lower deckers along senior staff just fine, even interweaving their stories; and Discovery which, particularly in the first season, creates characters by proximity to the story not by bridge positions. Tilly is important because she is Burnham's roommate, not because she's the chief of anything. Despite this Tilly's character is a fan favorite. Unfortunately, I think Discovery fell into the impulse of giving audiences more of what they want and that meant creating stories where a random cadet was a valued member of the team - and team was still mostly senior staff.
Discovery set a sort of precedent for this era of Trek by having only the XO and Captain wear gold. This of course gets mirrored in updated colors when they arrive in the 32nd century. It doesn't make a lot of sense unless, as you suggest, there's no clear pattern to the division color for pilots/helmsmen.
Oddly enough Geordi doesn't wear command red even though he is ostensibly a flag officer in command of multiple ships. He wore command red as a pilot and then never again, apparently, even as he obtained senior rank.
This is a question worth asking. As others have pointed out there sort of seems to be clear that the rules are the rules and business rules trump all other rules. The Rules of Acquisition tend to be the Ferengi Alliance's highest law. It's both a religious law and a practical one and I think therein is where the problem lies. You can't make profit outside of the constrains of normal ethics because whatever makes profit is what is ethical to do.
This is why so many contradictory Rules exist in this system. War is good for business and peace is good for business, and neither of these are statements on what is "bad" for business. There's nothing here that says not to do anything and I think in this way Ferengi ethics largely comes down to there's no precept that says I shouldn't do this and I was able to exchange doing it for profit so ultimately it serves a higher purpose.
And since it seems like there is a fair amount of legalize extortion that happens in Ferengi while it might be technically illegal to do slavery, it might be more profitable to do it and therefore on the whole you can come out with an ethical conclusion that is "good" especially if you're some mid-level Ferengi in charge of making sure that slavery doesn't happen and you're able to take a little bit of a kickback.