If a spell on the stack has split second while you control Teferi, you can't suspend creature cards since split second stops you from casting them, even though suspending them is a special action
Lets say I see your hand of Arc Trail and Vindicate, I will obviously take the Arc Trail and you will then be forced into Vindicating the 1/1 at a tempo loss if you want your Arc Trail
He also has a further ability, which can be used on your turn: whenever Scrooge McDuck banishes another character, you can play an Item card for no Ink cost
(To proliferate, choose any number of permanents and/or players, then give each another counter of each kind already there.) The value of X is determined only once, as Tromell's last ability resolves
Also included in each Starter Deck are two booster packs for Shimmering Skies , but those are (obviously) all random, so I won't be factoring in the cards I opened when evaluating these decks