Yeah, no beasts. And while assassinating Traya will be difficult, activating the MSG will not be so difficult... but as others have said, she will likely be on Korriban anyway and perhaps use Malachor as a decoy. So really that's what we should be discussing.
Additionally, I'm not sure that Traya will have access to the beasts from Dxun/Onderon. That was strictly Nihilus' operation, after the dissolution of the Sith Triumvirate. While it makes sense for her to have access to the Troopers, Acolytes, and Sith who are remnants of Revan's Empire, the facility at Freedon Nadd's tomb wasn't a part of her powerbase.