Mohg 100% did. His follower in the DLC (Alberich or whatever) outright says that Mohg had been under Miquella's influence the whole time, and he was the one actually being used in the end. Miquella more than likely planned for Mohg to be used as Radahn's vessel from the get-go and charmed him to make it easier. Think about it, Mohg was literally the perfect candidate. The body of a Demi-God which is probably necessarily to contain someone like Radahn, a forgotten and disgraced Omen child who wouldn't be missed, who lived in constant hiding from everyone. No one would notice anything and frankly wouldn't care if he died, which is SO sad, and which is why I think Miquella chose him.
As for Radahn, that's way more difficult to figure out. Radahn DID promise Miquella to be his consort one day, that is a fact. However, we don't know the circumstances behind this, what the specific vow was (i.e. why he agreed to it, though we can make some guesses), and most of all, if he was entirely willing to do it or not.
Remember, Miquella's ability is NOT mind control. He can sub-consciously influence people into not just liking him, not just loving him, but utterly adoring him and being literally willing to die for him. At least with direct mind control, it's often that the victim is still aware that they're being controlled and can resist to some extent. But Miquella's ability doesn't have any real downsides, he just makes people love him, truly and genuinely, and if you love him, why even bother wanting to "resist" what you can't even perceive as manipulation.
My headcanon/theory is that he charmed Radahn AND gave him a deal he couldn't resist, so Radahn agreed to it. But later, for whatever reason, Radahn went back on the vow, which led to Miquella sending Malenia, who was aware of the vow mind you, to kill Radahn so that Miquella could later take his soul. This is supported by Malenia's last words to Radahn in the Battle of Aeonia being "Miquella awaits thee, O' Promised Consort.". However, it's also fully possible that what they offered to Radahn was the war itself. We know Radahn was a pure warrior at heart, and he had immense respect for a fellow warrior, Godfrey. who's entire time as Elden Lord was spent fighting, killing, and conquering. Godfrey, or rather Hoarah Loux, was such a war lover that when he felled the last enemy in his path, it is said that the light faded from his eyes, his literal purpose in life that gave him motivation was to fight and kill, and that man was Radahn's idol, so it's not hard to discern that Radahn was pretty similar, though he had some degree of compassion and kindness in him which was part of why Miquella wanted him. Radahn had the strength, the lust for battle, and the compassion that Miquella sought in a lord. The idea that, to Radahn, a war with Malenia would be worth marrying Miquella so that Miquella could make the world a better place, genuinely isn't far-fetched, but who knows, it's still very vague.
Either way, it does seem that Radahn relented on the vow later on, as it's suggested that Miquella viewed him returning in the Land of Shadow as him "finally" completing the vow, which would mean that at some point he turned his back on it. Again, this could be why Malenia fights him. It's also possibly why Radahn fought so desperately to stay alive even when he was practically in hell, though in the base game that was because he had to hold back the stars, so it's still iffy, and weird because the whole Miquella thing doesn't even connect with Radahn's entire gimmick as the Starscourge, makes me wonder if Miquella even knew about the cosmic threats and Ranni's fate.
Anyways, I think it's possible that in his return in the Land of Shadow, Radahn was indeed completely under Miquella's control. It could explain why Radahn didn't utter a single word. He clearly talks in the lore, yet he doesn't say ANYTHING here? And if Miquella's ability can work on another Demi-God (Mohg, and arguably even Malenia though I think she just loved Miquella in general), it's absolutely not a stretch to think it'd work on Radahn, badass as he is, and he WOULD use it on Radahn, just in case. He has literally no reason not to, and not doing it could threaten his plans.
In any case, I'm leaning like 99% towards the idea he charmed both of them from the get-go and that they never really had a choice in anything. Radahn managed to resist it later on after some time away from Miquella, not under his influence, but we came along and killed him, sealing his fate.
I hereby vow! 
You will rue this day! 
Behold, a true drake warrior! 
And I, Igon! 
Your fear made flesh! 
Solid of scale you might be, foul dragon... 
But I will riddle with holes your rotten hide! 
With a hail of harpoons! 
