I have been using walkie-talkies while fishing for close to 20 years and mine aren't waterproof. I'm not saying waterproof is bad, just maybe not essential. When I go tubing I put mine is a small dry bag. If it rains while fishing, it goes in a pocket.
Also, I can't emphasize enough how much better & convenient being able to use regular batteries is. While rechargeables are nice, you have to remember to recharge them and the battery life is less than alkaline or lithium. Make sure any radio you consider can use both rechargeable & regular batteries.
Also, the GRMS dual function is nice but you are required to get an FCC license to operate them in the US. I looked into it once and deemed it not worth it.
Again, not to say a dual function radio is bad, it just may cost more and offer no benefit unless you plan to pursue the license, which BTW isn't free.