In terms of a broken connection stopping the speakers from working, it would depend in the parallel example where the break occurrs. If it occurred in the main feed, neither speaker would work. If it occurred in the feed from Speaker A to Speaker B, then A would work, but be would not.

You have the concept down correctly, but have reversed the names (Series vs. Parallel). This is kind of hard to describe with words, so lets try it again:
Parallel
- Amp (+ and -) to cooresponding Speaker A terminals ( + and -)
- Speaker A (+ and -) fed to Speaker B (+ and -) amp====SPeakerA====SpeakerB
Series
- Amp +-------(+SpeakerA-) ------(+SpeakerB-) ----------Amp -

Please see the attached file.

Regards,

BBIBH