Fabricelig : Swing will work in standalone, yes. Everything works in standalone, USB connection to a computer is just another way to send MIDI, and to configure the instrument via the MIDI Control Center application.
You also get individual swing amounts per sequence, if you want.
Atarikid : I'm afraid you won't be able to connect BeatStep to Beatstep Pro. Beatstep could only be sync'ed via USB, and beatstep Pro (like most USB devices) can not work as a USB master host.