The Baku apparently had a problem with the Sona staying on the planet, and had the means of driving them off. There's been suggestions of establishing health colonies elsewhere on the planet, what makes anyone think the Baku would agree to this?
Remember, no one wanted the Baku village, or even the planet itself.
If your house is in the path of a deliberately set back-burn intended to control a forest fire, yes the government can legally drag you out of your house.
The Baku were being move to prevent them from being harmed by the collection of the Particles.
In the meeting in the Enterprise conference room, there was dialog that the particles and the method of collecting them had been studied by the Federation/Starfleet's "best scientific minds."
There nothing to indicate this, the collection is to gather the particle for medical use.I'm sure the Celts would love the English to leave.
The Federation Council knew, they're the ones who agreed to a partnership with the Sona and sent the Admiral in.
And there was no "land grab" involved, it was already a Federation planet in Federation space.
Otherwise why did the Sona form a partnership with the Federation?
Norman's. Not English. The entire British Isles were invaded, certain 'Celtic' areas less so. The Celts were invaded by the Romans except in those lands, though some remained under Roman rule. History rather than politics. The modern Royal Family are German, and going back, Scotland was never conquered, Queen Elizabeth the First was from a Welsh/Norman background, and King James I (of England) was a Scots King invited to take the throne after her. The main 'conquests' happened hundreds of years before the stuff that gets remembered as a cause of trouble. England didn't even have an English speaking ruler for about three centuries (hence the meaning of the word marginalised) and the harrying of the north was pretty much ethnic cleansing. Your 'englishman' and your 'celt' are basically brothers at ground level, and it's the ruling groups for the last millennia or two who are the historical cause, especially when you throw doctrinal splits into the mix around Henry VIII (also Welsh, and ginger to boot.) Politics and the darker still side of human nature have muddied the waters since (not to mention Cromwell, or The Bruce stomping over Ireland and Wales on behalf of the Norman overlords before the family changed political views after his return to Scotland) British history is much more complex yet also simpler than the popular model used to influence people or make films with Mel Gibson in. Politics and History are things that are....fiddly. It's probably why most of the sort-of-tribal conflict in Britain is basically a class conflict rather than actually regional or national, with a few exceptions that have gone that way over time. Mind you....it's a bloody long time span, going from the Neolithic, up through the Celts, the Romans, Vikings..Saxons, Angles, Picts what have you. Look at Robin Hood for an amusing distillation.
It's a bad analogy for the treatment of Native Americans (who, it should be noted, were not stomped over by Elizabethan Empire building, and I believe groups in 'Virginia' were on quite friendly terms by the standards of the day...there's a big called Big Chief Elizabeth about it, though it's not really my area.) most of which comes later during the 'Nation Building' stage after the war of independence, and is of course wrapped up in religious zealotary and greed ultimately.
It's also a really bad analogy for insurrection, and the American model is slightly closer, though I personally wouldn't go as far as to use it as an analogy, except for the fact that the Baku situation is very similar to the Maquis situation, which Trek deliberately paralleled to Native Americans. Which is terribly clumsy in the film....the casting pales (hoho) into insignificance depending which point they are actually going for. In an odd way, the Son'Na are more like American colonists, as they are an expelled faction after a failed civil war (like Puritans).