Spike, Tournament Grinder The fact that Spike, Tournament Grinder is legendary caused an uproar in the community because it would be a very powerful commander
First off, they give you access to Izzet colors
Sadly, removing Merieke from the battlefield returns the creature to its owner (if its under your control) before it is destroyed, so you wont be able to take advantage of any death triggers this way
Punchy early drops like Cactuar, chocobo tokens, Loporrit Scout and Snow Villiers can only dominate until the true bombs start to hit the board
If you have additional combats, each combat step is treated separately, so at end of combat means the combat step that just happened
Usually, with those stats, both creatures would survive