As Aaron Forsythe stated in an article on the Ninth Edition set back in 2005: The truth is that the mechanic is so complicated and wonky that we would never greenlight it today, but it has been grandfathered into the fabric of the game, and it does fill a nice niche
The more you have, the more you have to lose
At bracket three, you can run all of these and still meet the deckbuilding criteria, which will give your deck a huge edge
If the target nonland permanent is an illegal target when the enters-the-battlefield ability tries to resolve, it won't resolve and none of its effects will happen
Check out preassembled decks either in person or check online what cards they contain and start figuring out effective strategies that use your favorite colors
Still, Flash and Flying are great