I think that having the character off-centre in such a long thin picture plane is quite a striking composition; I like it. The second one with the other two soldiers included looks a bit too centred and symmentrical. Maybe in the first illo you could include some additional background detail on the left to balance the composition and fill some dead space - or maybe use that space to put in some typography? If you do decide to include the other two soldiers (who I would quite like to see after seeing their tantalizing silhouettes!) maybe you could group them closer together?