I tried bfgminer 3.2.0, and it only detects my gpu.
bfgminer didnt work because you also needed -icarus-options 115200:1:1 --icarus-timing 3.0=100 to go along with your -S All argument.
Nope, not true for the actual versions (3.14 and upwards)
all you need is -S erupter:all
The last version 3.20 also produces less hardware errors than older versions or cgminer. (cgminer/older bfgminer has usualy about 1% hardware errors with USB Erupters, with 3.20 the hardware error rate drops to about 0.6%)