Normally, if a creature attacks, it cannot block the next turn
When it comes to deckbuilding all five cards will make decks more often than they wont, but they dont fit into Cubes as easily and are more difficult to justify drafting as they tend to fit the framework of the average decks of their respective colors worse
I wouldn't bother trying to push this up past bracket 3, but if you wanted a 5/c Spider-Man deck where the commander was just there for the colors, you could get up to all kinds of nonsense
Sure, you can keep making Cat tokens over and over again, but if you have tokens of another artifact or a different powerful creature, you can quickly make an army of massive creatures
Say what you will about Iconics, but they are pretty much locked in at one per color
Other body parts (such as tails) being above the bar doesn't make a creature a legal target