I was just reading a post on this sub about how ancient combat worked on a small scale, and I got curious about if researchers get any information from groups such as the Society for Creative Anachronism. (For those who don't know, this is an organization a little akin to a renaissance fair, but with more emphasis on non-scripted combat.) For obvious reasons, this sort of thing couldn't actually tell us what happened, but I wonder if we might be able to pick up some clues about how ancient arts and crafts (including war) worked...
I have some experience with historical reenactors (fencers, specifically), if that's OK. Feel free to delete if this does not meet the rules.
The reenactors get their information from the researchers, not the other way around. It's the researcher's job to discover history, it's the reenactor's passion to show it to the common folk. I know that reenactors sometimes can help with providing details on historical crafts by using them, but AFAIK it's quite rare.
Most reenactors prefer comfort to complete historical accuracy. Guys I work with will try to maintain the illusion by using proper period clothes and trying not to mix historical periods in their camp, using proper historical fighting techniques, not having any modern gadgets lying around, etc.. But then they make all their eqipment in a modern way with modern machines.
In case of fencing, only very few sources were kept. People extrapolated a lot of fighting techniques from what little we had, however we have no way of knowing which ones exactly were used.
On the other hand, there are the Living History guys. These people want to reenact history in the most accurate way possible and I can imagine these being the groups that could help historians practice ancient arts and crafts to determine possible usage.