IOTL: All Italian states were undergoing their own revolutionary phase. They were all initially fine with joining Sardinia in the war with Austria, though the courts were between lukewarm and hostile; they could not resist the "popular"* pressure.
So no, invading and annexing "allies" was not going to fly. Perhaps Sardinia could have gotten away with a takeover of Parma in a different context, but that's about it.
*As in, primarily by the urban middle class.