I think if all t1, all t2 and all t3 rewards would be the same for those bosses that I would be really bland, some items give character to a boss. Also'' 1x Small Train Ticket '' sounds like a really good reward for tier 2, better than any egg of the tier 3 rewards. Will the eggs hatch automatically? If so that would be a really crappy reward since you want h.a on most of those.
2 and 4 pve coins could also be boosted imo