I think that's a bad idea given that he also talked about things such as involving Trendon's wife's ex-husband and stuff.
Phin, it's obvious that the former employer concerned is The Lending Partners (no surprise there). As they're a legitimate business, they're probably not going to want to get involved in any kind of vigilante justice so you really need to make sure that whoever talks to them can keep it calm and rational.
Probably information on him that would lead to a successful legal action against him.
Has anyone even tried consulting a US lawyer about possible causes of action against Trendon? Tried having him served at his father's address? While any information The Lending Partners can provide is obviously useful in terms of background stuff, it's not relevant to the facts of Trendon's activities within this community. It
might push authorities to regard him as a serial fraudster, though. One question to ask The Lending Partners is whether they ever considered taking legal action against Trendon and why they decided not to ( does he keep himself "judgement-proof", for instance).
It might also be worth asking whether there was any indication that either Ryland Shavers or Zach Nakaska were involved in Trendon's sketchiness.