Salis is an easy option. She may leave her army behind since it may not officially be an EE, or more relevantly for her a ZU matter, but totally reasonable she'd go with her few droids to jump into the fight just for the sake of a fight. She's violent and good at it, and one of my strongest force users especially after I basically nerfed a different one. Also my second character.
Rocho Krul my trando force user mostly just out for the jaggannath points. Probably there either if there's a bounty on them or literally just because it'd be a challenge. Could do this either on his regular ship, or on his carrier, would depend on just what kind of forces you send. Exactly which of these two is more dangerous for the Grog wouldn't be clear, as Salis is definitely stronger in the force than Rocho and more likely to be able to use it well against them, but Rocho has considerable force awareness, uses most basic abilities very effectively, and enhances his physical abilities to considerable margins.
I obviously don't expect any of them to single-handedly destroy the Graug or anything it just depends on how things go. Also both of the above fought with the Byrn, so Rocho would likely just view them in a similar vein. Salis probably wouldn't but would be familiar with the potential advantages/disadvantages coming with their size difference and durability.
Another option just for fun could be
Xos Drikre. He's probably about Salis's level force wise, maybe above so long as he remains light side, but far from inherently as violent. He's a Baran Do sage, and is absolutely the kind to show up, and immediately try to reason with them instead of starting a confrontation. Easy option to put there because he's regularly guided by force visions.
Last two options who I'm lumping together cause they're extremely similar personality wise (and resemble Xos's choices, just...not as almost naively patient)
Kaiburr a Shard in a droid body trained by the Baran Do sages. And
Funo Civ who was my attempt at almost a traditional wandering jedi. These two probably would not be "top tier" so to speak for the fight. So I may end up having to make them end up retreating. Funo's good at defense but just may not cut it for offense, and Kaiburr who, while comparatively considered a master for the Baran Do, isn't inherently a warrior.