I place The Conspiracy late series 1. It would be early series 2 if not for the SkyPoint scene, which indicates the titular apartment complex is still under construction. The novel that SkyPoint debuts in is set between Something Borrowed and From Out of the Rain (Gwen in returning to work after her honeymoon), and SkyPoint has been open for a while, long enough for stories about people vanishing to spread among the residents (the case Torchwood investigates in the book). Jack does mention at the end that he knows the team has worked well without him, which would indicate the gap between series 1 and 2. Late series 1, very early series 2 at the latest.
Fall to Earth is set after The Conspiracy of course. Ianto still has feelings of inadequacy among the team and a desire to prove himself (trying to make up for Cyberwoman?). I'd place this early series 2.
Forgotten Lives takes place a few years after Miracle Day, I'd say 2015. Anwen is old enough to have started school.
One Rule is pre-series one.
Uncanny Valley is definitely after The Conspiracy (George Wilson is mentioned) and likely after Fall to Earth. Jack mentions he and his team are slowly exposing the secrets the Committee are hiding and shutting down their individual operations, indicating they are to some degree aware of the Committee and the threat they pose.
More Than This takes place in 2016 (the events of Day One are stated to have taken place ten years ago). Gwen can't have spent more than a few months fighting aliens with only a car as a base, necessitating the need to form a more permanent HQ (hence the events of the story).
Be sure to check out the indexes for the various Big Finish ranges!
So I'm all caught up on these, and I must say... do the main Committee stories all take place in Season 1? I suppose there's nothing to say that Uncanny Valley takes place around the same time as Fall to Earth, but Zone 10 most certainly takes place shortly after Uncanny Valley. I know that the BBC Audios and books and audio originals did a good job plugging the gaps between season 2 and Children of Earth, and then between CoE and Miracle Day, but so far Big Finish seem to be keeping to pre-series, season 1, and half a decade post-Miracle.
Like, if I were to line up everything chronologically, you'd have Tooth & Claw, a couple Committee related stories, Season 1 with some Committee stuff sprinkled throughout, then the next three seasons with audio originals and radio adventures and lost files and such before finally getting back to the Committee in Forgotten Lives. But then they weren't even mentioned in More Than This.
The Conspiracy and Fall to Earth (and Broken?) seem to take place between Cyberwoman and They Keep Killing Suzie. Uncanny Valley and Zone 10 need not necessarily take place near them there's nothing else to really suggest where they go, beyond a general "well they need to go sometime after Jack alerted the team to the existence of The Committee".
Also, I must say, having The Committee be behind Miracle Day seems a bit... on the nose? I don't know. Feels a bit forced. The stuff in Zone 10 almost makes it sound like they've got something to do with Children of Earth as well, but I don't think the dates match up for that, fortunately.