Well, I'd definitely vote for abandoning the original kink meme prompt and following the new direction, especially if there's some good bits that have come out of it so far. Let's face it; there's more than enough cliched average porno out there to read, and it wouldn't be satisfying for you to write it anyway. That's what more than half of this is about; it's supposed to be fun for you to write, not just the reader to read.

I agree that it's a stretch at best to get those two together without Tenpou acting as a catalyst between them. Even if they were physically attracted to each other, Goujun has more than enough at stake that he wouldn't throw it away on an attraction-based fling with one of his subordinate officers. He has more than enough self-control to ignore it, which is exactly what I'd think he'd do. Plus Kenren isn't so stupid or suicidal as to push a sexual harassment charge with his unwilling commander; he'd be discharged for it. Nope, I think that to get them together you'd need an added emotional connection between them that simply isn't there with these two characters alone. But add their mutual attraction to Tenpou into the mix, and the dynamics totally change.

Not only that, but even if I can imagine Kenren as a toppy bottom, I can't imagine that his pissing off Goujun during the act would get Goujun any more aroused or Kenren in anything but trouble. I'd think it would shut the whole thing down real quick. The only way I can see to do it would be to significantly change the personal characteristics of one of them simply to fit the prompt, or to take a Pizza Delivery Boy porn piece and just replace the words "Lady of the House" with "Kenren" and "Pizza guy" with "Goujun." Add cheesy soundtrack and voila! KenGou porn ready made.