I'm really excited for changes that would open up the action plots for this game! It was one of the things that drew me in, but my character hasn't had many opportunities to break into that side of the premise. So speaking as a player who hasn't ventured into the exploration aspect of this game but would like a chance to do so, I'm going to agree with the third option. Having separate mingles for slice-of-life and exploration/adventure would make it easier to know where to go if you're looking for one but not the other, and also make it clear which characters and players would like to build which kinds of CR.

I think it might be helpful for the exploration mingle to have different levels of involvement, like being on the "front line" of the action or playing more of a support role. This wouldn't have to be anything intricate (I'm constantly blow away by what you accomplish as a solo mod and I know that already takes so much work!), so maybe just a quick bullet point breakdown of heavy-action suggests versus lighter ones.

Also, at least for me, any option that is removed from the TDM is more appealing. I think that it's clear through the policy of not using TDM threads for AC that it's being held somewhat separate from the game, and if there were mingle posts that mirrored TDMs, there might be less incentive to tag an actual TDM since the same prompts would be doubled elsewhere with the added motivation of being used for AC.