"No one on this forum or any other internet forum is qualified to give you a medical opinion".
If you want a scientific opinion, you would need some kind of test that hasn't probably been done, it would be necessary to quantify the kinds of vibrations that are damaging, and a test of the planed route and it's load inputs. Good luck with that. Meanwhile many of us have actually done what is described and would know at a minimum if it was immediately fatal, which at least brackets the results somewhat.
Happily some of that route passes though areas that may not be too strict. Here we are not allowed to put child seats in the trailers, from what my wife tells me (Mmmm?). Or at least the kids are too small and the seats are not designed for helmets, and as we all know it is suicide not to wear a helmet while cycling, up here it is required for trailer use. So the forward facing upright seated posture does create risks, the need to wear a helmet creates risk, should the child not be strong enough to deal with the swaying of it's own head. Presumably a bit like what happens when a child is shaken back and forth for "disciplinary" reasons.
I was listening this evening to an interview with a Psych, who had studied Ohio children from cradle to 15-16 in one study. The study stimulated young children with new things. Colours, voices, and smells they were not familiar with. The stimulations were chosen for newness not offensiveness. about 20 % of the kids were very upset, and fall into a highly reactive group. At the other end about 40% were positive, low reactive types. These traits are permanent, at least for the length of the study. So if there is any truth to that, one would not expect all kids to benefit from a stream of new sights and smells presented on a tour. The 1 hr. interview was on CBC radio Ideas.