Your Commander must be a Legendary creature (or, in some cases, a planeswalker, if they have the text, can be your commander) and doesnt reside in your deck
As for the Red Elemental Blast versus Pyroblast question well, it wasnt always as easy as it is today (where the default of split them is the most common solution, thanks to cards like Cabal Therapy and Meddling Mage)
Twister X SPELL Quick-Play Pay 500 LP, then target 1 face-up Spell/Trap on the field
Land Color tag templates(None) Color tag templates(None) Forest Basic Land - Forest Color tag templates(None) Island Basic Land - Island Color tag templates(None) Ketria Triome ( : Add , , or .) This land enters tapped
These include Piglet - Pooh Pirate Captain, 003-184, John Silver - Greedy Treasure Seeker, 003-071, and, lastly, Pan's archrival and the card he is built to counter, Captain Hook - Master Swordsman