Your're right to have a singer - think of the associated band The correct letters give a hint. The same applies to the Across pairs (ie singer, band and hint)
radial 2 - plants names after Greek water nymphs -
the car is the American word for what we i the UK call a saloon (reversed) around/'across' A [with I the omitted letter].
If you try the two bands together with, ''+ English tradition'' you might get something for IQ on the net.