Life Tap Myrkul, Lord of Bones is an expensive investment so you want it to stick around once it hits the field
Yes, for the most part, colorless cards can go in any Commander deck
Sneak plays off an old mechanic called Ninjutsu which was also seen on Ninja creatures initially
(If you're playing Planechase, proceed to the next plane.) Playtest cards aren't legal for play in any tournament format other than Mystery Booster Limited formats
Thanks to Tegwyll itself, even if you have a strong board presence, you can use Tegwylls Scouring to reset the board at Instant speed, draw a bunch of cards with Tegwyll, and untap with a handful of fresh cards and three Faerie tokens
Surround it with a bunch of small creatures, attack, and watch life totals plummet