9a Encourage one clown to hold tears back (8) ??L?P?N? although it may be ?N?P?L?? because of the "thematic wish" (which I've not got yet? Where do I find it?)
12a Make tart flatter, round calamari at edges (9)
3d By the sound of it, sea ice, just over 500 metres, about to rise with more waves (9) The "just over 500 metres" is Li - a chinese unit of distance I think.