I don't think that WMF project grants would be a suitable funding source for *Signpost *work, for multiple reasons. I consider the *Signpost *to be "content", and WMF shouldn't fund content if it wants to maintain its immunity to lawsuits regarding user-contributed content. Also, there would be a conflict of interest between the journalistic role of the *Signpost *and the WMF; the *Signpost *should have significant financial, legal, and managerial independence from WMF.
Project grants could be a good source of funding for some work that addresses COI, although I think it would be good to keep in mind that WMF shouldn't be creating (or editing) content directly. I would be wary of using WMF funds to pay people to decide whether or not certain edits are appropriate. I think that training materials, and software tools to detect edits that look promotional or controversial, could be developed with WMF funds. I'd want someone who isn't reporting to WMF to make the decisions about the appropriateness of edits that are flagged for review (whether flagged by humans or technical tools, and whether or not self-reported by COI editors who request review). If a process leads to a community (i.e. not WMF and not COI editor) decision that edits are incompatible with community policies and norms, then at that point the matter could be (1) addressed directly by the reviewer such as by declining a proposed edit or reverting an edit, (2) referred to site administrators for community interventions such as warnings or blocks, and/or (3) referred to WMF for legal action using WMF resources. That's a long way of saying that I think that there are important technical and legal roles that WMF can have in helping to identify and deter COI editing, but WMF's roles should be be carefully separated from and in alignment with the community's roles.
Pine