Do you expect animals with human-like intelligence and dolphin-like bodies will fail to develop technological civilization? As a first approximation, I expect a community of modern human engineers (with basic technical background, but no specific knowledge) in dolphin bodies can manage to do that eventually,

How? You can not have fire (no magnesium, phosphorus and so on do not count, since you do not get them without fire), thus you do not get metals, steam and internal combustion engine. Since you do not get metals, you do not get precision tools, or electricity. You are more or less stuck with sharpened rocks and whale bones as a very poor substitute for wood (if you get them in the first place). I am very curious how you think a human or even smarter than human inteligence might bootstrap an industrial civilisation from there.