Spells with split second only prevent new spells and activated abilities from going on the stack until those spells resolve, but once the spell with split second resolves, you're free to interact normally with any other spells on the stack
As we will see, Owen Grady, Raptor Trainer can add certain types of Counters to Blue, Royal Raptor
Mana Echoes falls into the latter category
This will be a big card for the already popular mono-white aura archetype, which relies heavily on aura and enchantments to boost the impact of cards like Optimistic Scavenger and Ethereal Armor
Well, there are collectors out there looking for even the smallest of variations in color, alignment, or foiling
But note theres no way to augment your rolls, so a natural twenty is the only way youre gonna hit it