A FELINE IAGO

[eyo]

OKAY. I set up a profile just to give tips on this ludicrous achievement because no one else has put up a solution. It drove me crazy and I couldn't replicate all the steps, but maybe somebody else can crack the code after reading this.

THE GOAL

Make Claire OR Andre compromise their values to achieve their dreams.
Claire's version seems sad - like she'd have to let a bunch of animals die to get elected, somehow?? - so we'll go for Andre.
We will become a viral singing kitty sensation on Youtube, but fail to record a proper studio track. Helmut will then pressure Andre into selling ringtones using the sound directly from the youtube video, thus compromising Andre's morals and the final song's quality a great deal.
Then, if you openly celebrate despite Andre's clear misgivings, you will get the achievement.

General early guidelines (not thoroughly tested; may not be accurate)

• Showcase your love of music and hang out with Andre. I'm not sure if you should also be hanging with Claire sometimes or become a bastard cat who sabotages their marriage - maybe someone else can figure that out.
  
• You want to be LOYAL, INTUITIVE, and FUN-LOVING. At least for ch4.
  
• When you get some free "research" time early in the game, listen to the radio to figure out what a "hit" sounds like.
  
• You probably don't want Claire to ban Helmut from the house in Ch2. We can acknowledge that he's a jerk, but we do need him in the late-game. Therefore: make sure he doesn't come into the house and drink her alcohol, or if he DOES come in, coddle Claire to soothe her and then fart on Helmut to make her laugh. Again, if Claire gets pissed about Helmut here, it will interfere with your long-term superstar plans.
  
• It seems like you need to strike a careful balance of being kind to Maddox without COMPLETELY demonizing Helmut, but I'm not sure on this one.

The most important scene/s will be in ch4:

Normally on the Andre/fame route, you will get dialogue options to go fetch Helmut (who will be a weasel and sign you to some predatory contract asap - no Iago achievement for you). However, if you're relatively anti-Helmut (I'm not sure to what extent), CLAIRE will show up to film you singing your heart out and upload your video to youtube - putting you on track to go viral on your own.

When you're jamming with Andre (again - make sure you don't have ANY options to fetch Helmut), you'll have to choose one of the following choices:

• Support Andre by yowling along to the tune as loudly as I can. Making music is fun.(high loyal/fun-loving)
  
• Andre's sad his lucky break won't happen. Cheer him up by being enthusiastic about his music.(high loyal/intuition)

Then, when Claire shows up to record you, choose one of these:

• Hell yeah. I'm out of tune, but that's irrelevant. I was born to do this! (high intuition/researched hits on the radio)
  
• Art can't be forced! But if it raises my chances at fame, I'll do nearly anything. (high self-interest/researched hits on the radio)

After ch4:

• Evil grandma Nola should be the only dinner guest.
  
• When hanging out with Andre in a later chapter, instead of showing you his top playlist, he will be uploading your video to youtube.

After this... I'm not sure how it works - but you need to somehow AVOID actually recording your song in the studio, and either make Helmut the main party guest or ensure you don't have one at all in ch7.
Helmut should then call to pressure Andre "sell out" - this happens shortly after the family is watching a TV channel about polar bears in ch8.

Once Andre sufficiently is disgusted and disheartened, you have to choose one of these:

• if you're DOMESTICATED: I shut up and try to look pretty, as it's likely my new job.
  
  
• if you're FERAL: I ricochet around the room, tearing up the carpet, unable to contain my excitement.

Tadah, upon celebrating your own successful machinations without a care for your master's happiness, you are now a Feline Iago.
Sorry I couldn't write more detailed/complete instructions, but I figure having some information out there is better than having none. Hope this helps somebody get 100% achievements.