1) I'm not qualified to answer.

2) In my experience foam grips are more slippery when sweaty and cork grips are not as durable as foam. And just to complicate the matter, not all foam grips can be lumped in the same category because they vary wildly.

3) IMO the adavantage of shocks, if any, is not worth the added weight, complexity and cost. If you're planting your pole on anything other than solid rock the ground is a natural shock absorber.
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If you only travel on sunny days you will never reach your destination.*

* May not apply at certain latitudes in Canada and elsewhere.