Hard anchors
I'm not sure how you could effectively protect the hinges from ice impact without some kind of ice-breaker - like a piling, that would probably need some kind of permit. You may have to continue relying on luck and preventative maintenance.
For the rest of the infrastructure... Maybe you can bury some anchorages and bolt the raised dock to pieces of angle iron between the dock and the anchors. Chain would be an alternate material, and easier to get out of the way during the season. Some convenient trees might do well for anchorages, with some padding to protect them from the attachments. This would at least take the strain off your cables.
Good luck!
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