So now that I'm awaiting final approval on my character sheet, I wound up giving this game some thought while I was in the shower this morning. If I'm reading the original post correctly, the idea of eliminations is gone, yes? It's all about the Red Herring and finding them out.
In which case, I think the potential for drama between the contestants should be emphasized, as logically that would be the Red Herring's end goal. To stir up drama between the contestants. For example, what if you had two female characters that identify as feminists, but one is sex-positive while the other is sex-negative? Or the prude develops a crush on the sexually free, and then has to deal with their crush sleeping around with other people. Right there is potential for drama.
However, in order to keep things livened up, have the network pay for outings and events where the contestants are given mandatory pairings. Send them to a massage class where the playboy is paired up with a woman that doesn't like being touched intimately. Or give the ladies an allowance to go on a shopping mall trip where each guy has to follow the girl around. Imagine the clueless guy saying "I dunno, it gives you a bit of a muffin-top look" to the vain tease that gets high on guys looking-but-not-touching?
Think something along the lines of The Real World, where the intent is to incite drama through clashing personalities. This will provide fuel for the Red Herring in a manner that allows them to manipulate everyone's emotions, creating even more chaos, all while trying to keep people from realizing that they are the Loki element.
Try and implement some of these concepts to the design of the house, too. Perhaps the walls between bedrooms are thin enough that you'll always hear when someone is getting it on. Have the gratuitous hot tub outside. Perhaps have a lounge equipped with a bar and, in the room center, a stripper pole and small stage. (Post write-up edit: ah! An S&M dungeon in the basement! That will surely go over well!
Lastly, figure out what sort of network the show would play on. After all, part of the expectation is that these characters will be engaging in carnal activities, correct? Will the show then be aired on a pornography channel? Or perhaps will it be streamed completely online? Will all of the cameras be hidden and placed throughout the house, or will there be a film crew within the house as well (as there obviously will need to be one for when they go on outings)?
The only other thought I have is that, perhaps each contestant should get some sum of cash for being on the show anyway. This way the more introverted personalities have greater incentive than the potential prize at the end.
I imagine I may sound a bit presumptuous with some of these thoughts, but the intent is merely to get brainstorming a bit in hopes of attracting more interest to the idea. I think there's a lot of potential here. I also think it might help if you edit the first post periodically to remove any prior thoughts and brainstorming, presenting the final idea and then noting any other concepts by the end. As for the length of each season, don't worry about that for now I'd say. If you structure the game by outings and events within the house (arrival, first outing, a holiday or celebration (say, superbowl?), second outing, first snowfall in the house, etc.) then the game will be able to go at its own sort of pacing while also freeing all players to make suggestions as to the next "phase", be it an outing or just a day to explore the characters within the house setting.
Hopefully this will get some additional ideas kicking around in everyone's heads. As I said, I think the idea for the game has a lot of potential, but for some it will need to be showcased. And if I come off as an asshole, apologies, that was not my intent.