Calendars and diagonals

A long calendar is short the 30-day call and long the 60-day call at the same strike. Which outcome hurts it most by the front expiry?

• The stock sits right at the strike
• The stock moves far from the strike in either direction
• Implied volatility rises

In tastylive's diagonal check, what should the short option's premium be compared with?

• The long option's intrinsic value
• The long option's extrinsic value
• The width of the strikes