You're right about the lighting conditions, I was going to go along but decided against it when I saw the weather, so full marks for giving it a go.
You seem to have captured the decisive moment of the muskets firing well enough, but events like this can be tricky to frame, often due to lack of space around the performers (little opportunity to give space for the gun to fire into without picking up distracting clutter in the frame), or a jostling audience around you restricting your movement to try a different angle. Having shots with the modern crowd in the background with cagouls and hi-vis clothing is also a bit of a distraction.
If I'd gone, I was planning to take a 100-400 zoom to get in tighter (as well as a 24-105 general purpose zoom), trying a portrait format at times to pick my framing if a landscape shot couldn't avoid unwanted clutter to the left or right. Perhaps also trying a reportage type approach, capturing the facial expression of the audience in response to the battle re-enactors? However, the approach you take will usually be dictated by the space you've got and layout of the performance.
You'll probably find quite a few of the battle re-enactors are up for posing for the camera singly or in small groups too, if you ask nicely and catch them when they've got a bit of spare time a little before or after their 'show'. Welsh Row and the Market Square might be a good hunting ground for this sort of thing? Choose a suitable background and you can get some nice looking period shots without modern clutter to date it.
You may have tried some of the above ideas, but if not, I hope the above is useful.