Enduring Tenacity is the best of the bunch, as its a mana cheaper than Sanguine Bond, an EDH staple
Note that even though the last week of previews was cut short by the full set spoiler, the last Friday was still officially part of the last preview week, so it was still considered two (or in the case of Scars, three) weeks of official previews
The addition of Red to the possibilities means that we can take advantage of cards like Devastating Summons, Feldon of the Third Path, Flameshadow Conjuring, and Godsire to create either massive creature tokens or copies of tokens that were meant to only last the turn, but can now stick around
The Guildgate cycle is pretty cheap on the cost, and I doubt this will be too pricey, so this is a nice budget mass color maker there
Getting to Max Speed is incredibly difficult, but Vnwxt does offer an ability that makes it worthwhile