If you see two mana open with one being black, you always have to be wary about drawing cards as Orcish Bowmasters could be around the corner
These are known as "Celebration" cards
Red can easily generate mana advantage as well, be it through bursty rituals (Irencrag Feat), treasure tokens (Dockside Extortionist), free spell/polymorph effects (Fires of Invention, Tibalts Trickery), or the occasional outright mana dork/discounter/mana multiplier (Leyline Tyrant, Mana Echoes)
Errors do not affect the characteristics of the character in any way.
The book on combating Swiftspear decks has been written, and it wont change until you force it to
More affordable plays include M Gyarados EX (Full Art) 115/122 BREAKpoint and M Tyranitar EX (Full Art) Ancient Origins , both hovering below $90