A different way to plan these two drawings is to treat them as two connected frames of a tiny story about the same boy, and to test each pose with a quick silhouette check before adding any detail.
Think of the two scenes as a contrast pair on purpose: the catapult scene as a quiet, focused moment (still body, narrowed eyes, one small precise action) and the football scene as a loud, chaotic moment (full-body motion, splashing mud, an open joyful expression). Planning them as opposites from the start makes each pose read more clearly on its own.
Before adding any line detail, block each pose as a solid dark silhouette shape in a rough thumbnail. If the catapult-aiming shape and the football-kicking shape are each recognisable purely from their outline, the pose is strong enough to carry the final line drawing; if the silhouette looks like a person just standing, the pose needs to be pushed further (a lower crouch for aiming, a higher kicking leg for the football action).
Only after the silhouette reads clearly should the face, hair, and clothing be added, checking each time against the reference image so the character never drifts from Rohan's established look.
As a last check before finishing, run through a short list: does the character still look like Rohan, does the pose clearly show what he is doing, and is the line clean and confidently drawn without extra background clutter.
Working this way keeps both illustrations tied together as one visual story while making sure each pose is strong enough to be read at a glance.