obviously i don't know your set-up, staffing, sqn interests etc.. but speaking from a sqn that appears to have all the equipment of a decent sized university athletics club rotting in a storeroom, i'd be very tempted to concentrate on the team and fun type activites - rounders, football etc.. and avoid the serious and more individual stuff like javelin and shot like the plague...
what proportion of your cadets would be interested?
does your sqn have the skills to actually coach them in technique?
does your sqn have the staff to manage 30-odd cadets playing rounders, football and tag rugby while also running a javelin/shot range and providing individual cadets with coaching?
i'd be very wary of a fad that might try and turn your sqn into an athletics club, not least because your staff and cadets will demonstrate in short order that if they had wanted to join an athletics club they would have done so.
my advice would absolutely be stick to the fun, team games and leave the specialist stuff to Schools and athletics clubs - its unlikely you can compete with them in terms of staff skills and time, so don't bother trying.