A Gar Saxon appearance isn't impossible as they could opt to do a flashback scene or two, maybe recreating part of the siege. If for no other reason than to give the people that haven't been following the animated shows some context as to who Ahsoka actually is (they still haven't even been explicitly told she was Anakin's apprentice.)
And between Sabine's involvement and that Mandalore is one of the main common threads of these three shows (though I think 'Book of Boba Fett' aptly proved that these aren't individual shows, but an extended anthology series where sometimes the title and theme song is different.) I think it's well within the realms of possibility.
Pie in the sky hope: a live action recreation of at least part of the siege of Mandalore, including at least a glimpse of the Maul fight. I mean they already have the choreography worked out, and they've even already used the same stunt performer that doubled Ahsoka on the mo-cap stage, so it's just matter of getting her and Park into make-up & consume this time! Hell, now the Stevenson is booked, the major character they don't have an actor on-hand for is Ursa Wren. (That we know of.)
I mean seriously, they already have Ahsoka (though in this case I'd rather see a body double + Ashley's voice) Sackoff & Morrison are easy gets, plus even Ewan and Hayden are back so it's not impossible to deepfake/de-age them back to their 2003 selves for a scene or two.
Hell, if we really want to be crazy, why not get the complete live action version of
this scene? It's only a question on how much they want to spend getting Sam Jackson to come down and have dots painted on his face (bonus points as they already have the digital assets for mid 90's Sam from Captain Marvel to use as a base), and if Frank Oz is willing to record a few lines of Yoda dialogue.
Alternatively I guess he could just be playing Saxon's son who he'd dumped at an Imperial Academy, and who would understandably have a grudge against Sabine (and be none too fond of Ahsoka, either.)
