Looks like a fun day and some of those fish look pretty decent size too. My personal minimum size is 6.5"-7", depends on what lake i am fishing. The way they fillet, even the smaller fish have a good chunk of meat and can easily get all the belly meat.
Best freshwater fish? Thats a tough one, would say in the top 3 but hard to make that order, i like them all. Y.Perch have pretty firm meat similar to bluegill, where crappie are more flaky when you pull the meat apart after cooking.
Yes, ice them down. Just wait till you eat them after an ice fishing trip and they go straight from ~40 degree onto the ice and never thaw till you clean them -you will tell a difference in taste no doubt!