Don't call the competitors pupils

Since we mention that we don't require them to be in education,
calling them pupils doesn't make sense.
Fix possesive 'its'.
There's only one team being talked about directly here

(Otherwise, it should be "teams' abilities").
Move footnote after full stop

Per apparent standard rules for footnotes.
Capitalise "Competition" where it references the event

This helps distinguish it from the other mentions, while also making
it consistent with Kickstart.