Re: Was it ever confirmed that Daniels was Worf's replacement on 1701-
I've always assumed he was too, though I have wondered about the guy who gives Picard the nod outside Engineering. When Data pulls open the manual override panel for the doors he looks to Picard, and then Picard looks to a random middle-aged security guy who nods that he's ready.
I know the nod is because he's right there next to them and this is a very tense moment - but
why is he right there up front next to them? Why would Picard need to check with this guy before he gives an order? The only reason I could come up with was that he was the security chief and the nod meant "my security team, of which I am chief, is ready and since I am security chief it's up to me to report that to you. By nodding. Which I have now done. Please proceed."
He's also the first member of the Enterprise crew to take down a drone, setting an example for the rest of his men like any good security chief would do.
And he gets his own closeup, so he must be important.
I've not got the disc to hand at the moment and none of the grabs on Trekcore show a clear shot of this guy's rank pips, but I think the evidence I've presented here is pretty conclusive.
Your mention of SFDebris there makes me remember his review of (I think) The Die is Cast, where he notes that Kira's specifically the Defiant's weapons officer and Eddington's specifically its security chief. (
"The one ship in the fleet that says put one person in charge shooting any enemy ships, and another in charge on shooting any boarders, is the U.S.S. Ben Sisko's Motherf**kin' Pimp Hand - where every job description tags on to the end of it 'and shooting things'." 
)
Maybe it's the same on the E, Daniels was tactical officer (and on break when Worf took his bridge station near the start of the film) and this other guy was security chief? And either he didn't make it off deck 16 or (more likely IMO) was just being such a damn fine security chief that he didn't want to take time out from killing Borg (with his bare hands) and had Daniels running back and forth with messages?