They could also be used as the Chasseurs Cylistes. For the early period the head swaps with those that wear french kepis, for the later period they'll do as they are. The bicycles can be obtained from HäT bicycle sets already released. If you feel adventurous, you can even try to make them wear those folded on their backs.
Many thanks AP for taking your time to post these very nice images.
I thought of cyclists, but found the existing sets of everybody cycling a bit monotone. Cyclists prone behind their bike, or indeed advancing on foot with their bikes on their backs would be an intersting addition. Since I doubt there will be a set of those, I might give a conversion a try.