Some clues:
Puzzle 342 received an near miss from SCGrew. He got the right composer but the wrong work, and his dates seemed rather suspect. Indeed, his dates suggested that the work in question was composed three yuears later than it actually was, (according to the programme notes at my disposal, anyway).
Puzzle 344 is from a short work by an American composer known also as a conductor or modern music. One of his better known works consists of stolen property, and was performed and recorded under the direction of one Leonard Bernstein. The 'theft' was from Bach. The current work, as mentioned earlier, has a job-seeking allusion in the title.
Puzzle 345 is from the ballet music of a one act opera. It is usually encountered, as here, in the form of a concert suite. This is an arrangement, by the composer, for 2 pianos. It dates from around 1920 (give or take a couple of years). You will feel one of these for not getting it sooner.
