You could probably have joints split into 1/3s, and then have some joints, some diced and some minced.
A good butcher should really be able to advise you on the quality of the meat once he starts to butcher it, and how best to have it butchered.
Not sure what advice to give re the toddlers though, but hopefully if they enjoyed the lamb they will like this too and are young enough to accept it.
Mind you I seem to remember my mum telling me that as a toddler she couldn't tell me or my brother that we were eating lamb as otherwise we wouldn't eat it, and we didn't keep our own sheep!