Rotation and reprints Core Constructed uses rotation
Legality depends on the tournament format -- Squadron Carrier can be legal in some formats and banned or restricted in others
Ideally well be able to find another black card or two that fits into this archetype, but that will take some hours scouring Gatherer
The protection the sword gives means that not only can your opponent not target the creature with spells and abilities, much like Hexproof, but also means that their creatures, planeswalkers, and other permanents cannot interact with it either
Boros uncommon gives +2/+2 until end of turn at a reasonable price of one mana, or it provides an expensive Lightning Helix, which will usually kill an opposing creature and help offset some damage with the lifegain
The Cleave cost must be on a entirely different color scheme from the initial casting cost