I don't have first-hand experience, but I'd say the "wet ice" means ordinary ice. It'll definitely melt and become 'wet ice'. I've seen the EPS (White, crummy) coolers packed with dry ice & shipped on other airlines, but don't know how CO would treat this. With these coolers, you could easily punch a few holes to make it 'vented'.

Just save everyone else and don't go skimpy on the dry ice! I was in YUL a few weeks ago waiting for my bag to come off of the belt and it REEKED of old fish. I said that if my bag smelled, there would be hell to pay! Luckily it must have been on a different flight because my bag was fine!