The "iffy" bit is far from just conjecture. Neil Warnock has a long record of having his transfers queried by the football authorities starting from when he was QPR manager when he arranged the transfer (through the agent Willie McKay) to bring Joey Barton from Newcastle and there were questions about whether the transfer funds were fully and properly accounted for.
Further FA enquiries followed when he was manager at Sheffield United, Crystal Palace and here at Cardiff City concerning player purchases through agencies employing his son James.
All of the above are on the public record with a bit of research so can hardly be described as conjecture.