Neither Sabat or Schemmel has what I'd call a "whiny, kind of effeminate voice" so to me there are two possibilities.
The first is that Ty was misremembering and mistakenly thought of someone else's voice, which could easily be the case given he's not terribly familiar with all of these individuals. There are several other clues that fit for Sabat, but after Vic's testimony that Sabat was one of the people contacting KC, that would mean he certainly wasn't keeping his hands clean. That's why I'm more mixed on putting Sabat down as Iago. Also being an owner of the recording studio would make him a principal, not a vice-principal of a company.
The second is that it really is D.C. Douglas who also fits a lot of clues, but does have a voice that I could see Ty describing that way. Go queue up some videos of all three of those people talking and just listen in the background without looking at them as a person. Both Sabat and Schemmel sound like generally regular dudes, but Douglas has this weird inflection and slightly off intonation that doesn't seem masculine, even though his voice isn't particular high.
I'd put Schemmel as Renfield because he's kind of a patsy, and Nick later stated that Renfield's importance might have been overstated. Schemmel seems like the kind that might retweet and fall in line, but probably not the kind of person to go out of his way to cause any mischief himself.
Edit: After listening to some of the voices of the other suspects, Adam Sheehan also fits as far as the voice goes since he also throws a bit of femme inflection into his speech, probably just as a result of living in San Francisco. He doesn't work for either Funi or RT, but would be a Vice Principal at Crunchyroll and VRV as the Director of Events. The affidavit of his makes it seem like he really hates Vic and has probably been smearing him much more behind the scenes than he has publicly. He also got into a spat with Todd on Twitter.
