In terms of how fast the A380 was taxiing... I'm sure people who filmed the video know exactly how fast it was speeded up, or whether it was in real time speed, or slow-motion.
The other thing is that the A380 seems to come to a complete stop very soon after hitting the other plane, so did notice the incident and were going slow enough to stop in a reasonable distance (given the weight and momentum of such a large plane.)
Neck injuries and whiplash are a concern for passengers in the smaller plane whether or not they hire lawyers. You can't get whipped around like that without some risk of injury, as the seat belts securely fastened wont stop your head and neck from getting rapidly tossed sideways.
This will be my only comment, as I am by no means an expert.