Stonehenge and the recumbents [it's all about the recumbent at them- i've been to enough] are not true stone circles and the recumbents do seem to have had a fire at the start [probably to clear the ground]. It really does seem to be different where you are in the country which suggests different things were going on all over, therefore it was probably very regional as to what went on , i can almost hear the dancing feet down here in cornwall.
I think the name recumbent stone circles tells us what type of monument it is . Recumbents also have burials associated with them , as well as ring cairns . Stone circles in the south west had charcoal deposits e.g. at Ferworthy the entire inner space was covered in charcoal, Brisworthy and the Grey Wethers also had charcoal deposits , Boskednan had a cist .Hurlers northern circle was paved with granite ,Duloe had an urn with a cremation . "Swept clean " and don't like excavating them "quotes ?
Things that were probably added later, not by the builders! burl, barnett and lots of others [ i'm not spending my night going though 100's of books, sorry they're boxed up] both said as much and both have excavated places.
I have already mentioned that later insertions into stone circles were commonplace but in many cases there were aretfacts and activity prior to the erection of the stone circle and noted by Burl and Barnatt .
Yes but Probably by different sets of people, the wooden posts at the sanctuary were older than the stone circles which were built long after the posts had rotted away, so therefore some people may have liked to mark ancient wooden structures with circles of stone, as if to mark the spot, maybe to stop it getting lost from view [if the posts had rotted and there was nothing left to see].