As to my second investigation target (N1 was Joth, who's town), I peeked at Robz888 last night, out of curiosity if he would be trying a "D1 lynch your partner" play on Dsell (the lynch didn't happen until D2, but Robz was pushing what felt like a really weak/bad case D1).
Robz is also town.
Of course in both the case of Robz and Joth, they aren't 100% IC's to me, because there's the chance my targets were bussed/switched - however I find that very unlikely. I didn't breadcrumb that I had two Investigative cards in my hand D1, so I could've effectively played anything that night. Scum would've had to guess not only that I was playing that card type, but also which of their members I would be investigating (in order to switch themselves with a townie). It just doesn't seem to be all that likely.
N2 they might have guessed that I would follow up with another investigative role, but again, in order to bus my target effectively they would've needed to guess which of their members I would target - and given Robz push for a Dsell lynch, if he was indeed scum he would likely be the "hidden" one - ie. The one they were least worried about being investigated.
So both nights I find it rather unlikely that my results were compromised. Not impossible of course, but unlikely.