I assumed when FW refers to "so and so was going to come up here and try to kill him (Billy)" she was speaking in hypothetical terms about the people who she believed killed the Rhoden Family. That said, it's very possible she will make up some story about a fictional or real person who she'll claim was the murderer. Recall in her interview with Cleveland.com, she said she thought it was Isis or some cartel.

Maybe she'll try for the butler, in the library, with a dagger.
Also note at the beginning of the linked motion, FW's attorneys make a false claim that, when investigating the Rhoden/Gilley Massacre, BCI discovered evidence of a cockfighting operation.
That's untrue, there were only animals there that Frankie was raising. Based on that embellishment of the facts, it appears the defense teams will try to blame the Rhodens for their own murders, claiming mystery people associated with all kinds of alleged activities the Rhodens were engaged in were responsible for the massacre of 8 people.
The problem with that approach is the only evidence at the crime scenes and elsewhere, including recorded phone calls, ballistics, DNA, texts, security and game cam footage, etc. point to the Wagners.
JMO
ETA: I've always wondered why Fredericka Wagner allegedly only went to the trouble to protect her son, Billy, after the murders by buying him TWO (2) BPV's, but did nothing to protect her grandchildren?
If FW cares so much she's willing to testify on behalf of her grandson George, why didn't she buy two BPV's for him? How about Jake? As an "innocent" person who knew nothing about who might have killed the Rhodens and HG, why did she only care to protect Billy and her daughter?