Can you pay the Accelerate cost when playing a unit with Heedless Resurrection?

Ruling: Yes. When an effect instructs you to play a card "ignoring its cost," it only sets the base Energy and Power costs to zero, but you may still pay optional additional costs like Accelerate.

Sequence:

• Play Heedless Resurrection and kill a friendly unit that meets the cost requirement
• When the spell resolves, play the target unit from your trash with its base cost set to 0/0
• Declare you are using Accelerate and pay its cost
• The unit enters the battlefield ready

Nuances:

• The unit you kill to cast Heedless Resurrection must have printed costs that meet or exceed the base cost of the unit you're playing from trash
• Accelerate's cost is added on top of the zeroed base cost