Yes. They are all militia-men. Assuming the print is from or about 1815, they are all members of Belgian militia units and therefore not part of the field army. Possibly the artist intended to show men of the reserve army. This included regular units as well, however.
Certain detail not show up in other works, but are known (to me) as regulation. Others are clearly not. Some of those are not mentioned in a quite detailed list of officiers equipment. The list was intended to show how much an officer had to buy on joining a regiment (the milita carabinieers in this case) and it would seem extremely unlikely that any item of equipment used, like a pouch and belt would have been excluded if it was used.
Orange cuffs as on the officers frock coat were non-regulation and no inspection report that I know of mentions them, then or later.
Notice, by the way, that the illustration is not finished: the officer on the extreme left should have a black plume but apart from the red top it is uncoloured. So are more pieces of clothing.