1. I've never seen a modern-style risk assessment, if that's what you mean. We don't have sufficient data for that. But we do have 600+ shipwrecks in the Mediterranean just in the early Roman Principate alone, and we can compare the number of wrecks (generally) between the eras to what we can surmise about the rough overall amount of shipping in each era. We can also come to some limited conclusions based on modern weather data (limited, because the climate of the Mediterranean two millennia ago was quite different than it is now). We know that the Med. often featured currents at odds with the winds; that in general the winter months were more dangerous than the summer months; that certain areas were extremely dangerous due to their geography (Cape Malea, or the Carthage approaches, or the Marseilles approach, e.g.); and that Roman sailing technology was somewhat limited and did not progress much over the long centuries of their hegemony, for whatever reason. (although, note that the lateen sail became very common during the Imperial period, a significant innovation; before this, the large square amidship mainsail, typical before the lateen was added to the repertoire, was powerful with the wind, but struggled very much in adverse conditions).

Having said all that, catastrophic loss of the big merchant vessels in any period was probably relatively rare. Because there were so many known risk factors, there were also effective strategies for mitigating that risk (don't sail during the winter unless the prices demand it; don't approach [x] harbor if the wind is not cooperating; don't overload; etc). Cohen argues as much, and points out that our very scattered literary evidence pertaining to shipwrecks indicates they were traumatic and unusual events, much like modern airline crashes (Athenian Economy and Society: A Banking Perspective 1991).

2. Risk Management was invented in the ancient world, and there were contracts which shared risk between partners or "corporations" in mercantile ventures large and small. Many were predatory in nature. I wrote more about shipping contracts and predation (from piracy, but shipwreck also works) over here.

3. I don't know what you mean by this question. If you mean: were ships recovered, the answer is no. Once she went down, she was gone. The Romans of the Imperial period technically possessed the technology to raise a wreck if it was within free-dive depth, but the cost and effort associated was prohibitive. I don't actually know if shallow salvaging of cargo, formal or informal, went on in the ancient world. That would be a great question to ask the sub: do we have examples of ancient shipwrecks which seem to have been looted of their cargoes in antiquity? Certainly we find many, and some even in rather shallow water, which still appear to contain all their cargo in the sunken hull. This database shows hundreds in less than 10m of water. This one must have been in quite shallow water when she went down (the area has since silted up), and she still contained a lot of transport cargo and a few valuable objects, like the bronze lion-paw stands.