Rowan, Scholar of Sparks // Will, Scholar of Frost — ruling 1

Neither face’s first ability can reduce colored mana requirements of spells you cast.

Rowan, Scholar of Sparks // Will, Scholar of Frost — ruling 2

To determine the total cost of a spell, start with the mana cost or alternative cost you’re paying, add any cost increases, then apply any cost reductions (such as that of Rowan or Will’s first ability). The mana value of the spell is determined only by its mana cost, no matter what the total cost to cast the spell was.

Rowan, Scholar of Sparks // Will, Scholar of Frost — ruling 3

For Rowan’s emblem, you can pay {2} only once. You can’t pay more to copy the spell more than once.

Rowan, Scholar of Sparks // Will, Scholar of Frost — ruling 4

For Will’s first loyalty ability, any effects that modify a creature’s power and/or toughness without setting them to a specific value (i.e. ones that don’t affect base power and/or toughness) will apply after its base power and toughness are set, regardless of the order those effects were created. The same is true for counters that modify its power and toughness.

Rowan, Scholar of Sparks // Will, Scholar of Frost : règles, fonctionnement et interactions (MTG)

Rowan, Scholar of Sparks // Will, Scholar of Frost is one of those cards players keep asking about. Here is, in plain words, what its official text says, the rulings published by Wizards of the Coast, and the combos players actually run.

Official card text

Instant and sorcery spells you cast cost less to cast. +1: Rowan deals 1 damage to each opponent. If you've drawn three or more cards this turn, she deals 3 damage to each opponent instead. −4: You get an emblem with "Whenever you cast an instant or sorcery spell, you may pay . If you do, copy that spell. You may choose new targets for the copy." Instant and sorcery spells you cast cost less to cast. +1: Up to one target creature has base power and toughness 0/2 until your next turn. −3: Draw two cards. −7: Exile up to five target permanents. For each permanent exiled this way, its controller creates a 4/4 blue and red Elemental creature token.

How it works : Rowan, Scholar of Sparks // Will, Scholar of Frost

Original English text — Wizards of the Coast / Scryfall

#1April 16, 2021· Wizards of the Coast
Neither face’s first ability can reduce colored mana requirements of spells you cast.
No other card is named in this ruling.
#2April 16, 2021· Wizards of the Coast
To determine the total cost of a spell, start with the mana cost or alternative cost you’re paying, add any cost increases, then apply any cost reductions (such as that of Rowan or Will’s first ability). The mana value of the spell is determined only by its mana cost, no matter what the total cost to cast the spell was.
No other card is named in this ruling.
#3April 16, 2021· Wizards of the Coast
For Rowan’s emblem, you can pay only once. You can’t pay more to copy the spell more than once.
No other card is named in this ruling.
#4April 16, 2021· Wizards of the Coast
For Will’s first loyalty ability, any effects that modify a creature’s power and/or toughness without setting them to a specific value (i.e. ones that don’t affect base power and/or toughness) will apply after its base power and toughness are set, regardless of the order those effects were created. The same is true for counters that modify its power and toughness.
No other card is named in this ruling.