The beach scenes were shot at a beach north of Blackpool that I’m blanking on the name of
Jedi Temple Guard mask
Yeah, that one certainly grabbed my attention. On the list of "things from animation yet to be seen in live action" I didn't think THIS show would the one to check this item off the list.
Though one can't help but question how he gets away with prominently displaying what is almost certainly contraband.
Perhaps it's part of his cover? Bribe some Imperial official to look the other way and quietly give Luthen's comings and goings a pass. Since they'd thing it's just because he's trading in dusty old knick-knacks, there's no real harm in or serious risk in it, especially since most of his clientele are Imperial elites (besides, most of them are fakes and replicas anyway!) That way, Luthen gets some low-key protection without the risk of raising any serious suspicions; hiding in plain sight.
I mean, the ISB would be a fully new organization, with different structures, responsibilities and ranks, so I don't necessarily see it as a demotion either, especially given that Yularen ends up with more power as an ISB colonel than as a Republic admiral, given ISB's reach and capabilities. I doubt Yularen felt there was much of demotion there, especially since he would be among the first to support the new order.
I think it's safe to say that being one of the senior figures in the Empire's secret offers far more influence, prestige and MONEY than any serving navy Admiral (on top of presumably keeping his Navy pension.) As a bonus, he mostly gets to stay home on Coruscant, keep reasonable office hours, and he almost never gets shot at anymore. So yeah the idea that this is a demotion is just crazy. It's a career change, for sure, but an upwards one.
It's also probably worth remembering that the GAR's non-clone officer corps was mostly drawn from local judicial forces (since there hadn't been a standing military on that scale in a millennium.) So there's every chance that security and intelligence is actually where Yularen originally came from before the war.
So going back to that world in part the train the next generation of security agents (Kallus among them IIRC) seems like a perfectly reasonable post-war retirement. Especially considering the alternative at the time would have been overseeing endless separatist hold-out mop-up operations, maybe bucking for a military governorship of some mid-rim planet and having to deal with all the headaches and politicking of the other Moffs.
Syril switching sides wouldn't be unprecedented even in Disney Era Star Wars. Agent Kallus defected to the Rebellion after being one of the primary villains at the start of Rebels and went on to be one of the three known persons to use the codename "Fulcrum," Ahsoka and Cassian being the others.
It's not impossible, but I really don't see his arc going that way. Syril is a middle-class climber. An incompetent, over-eager try-hard. He's the Star Wars version of Arnold Rimmer.
If anything, I think he's going to double down on his commitment to the Empire. After all, he doesn't resent the Empire for what happened, he resents what he sees as corporate corruption and dereliction of duty. On a more personal level he may also blame Cassian, but if he ends up going after him (which seems likely) it'll be in an attempt to clear his name and improve his standing, not to switch sides.
