No, cached resources do not count toward the calculation of resource costs on a dragon when activating an "end game" ability. Cached resources are explicitly stated to remain in place until the end of the game and cannot be spent. Additionally, cached resources are worth 1 VP each unless otherwise specified, but they are not considered part of the resource costs printed on a dragon card.

This conclusion is supported by the following rules:

• Cached resources: "Cached resources remain in place until the end of the game (they cannot be spent) and are worth 1 each, unless otherwise specified." (Page 8)
• End game abilities: The rulebook does not mention cached resources being included in resource cost calculations for end game abilities.

Thus, cached resources are treated separately from the printed resource costs on dragon cards and do not contribute to those costs.

Source: Page 8

Source: Wyrmspan Rulebook (pp. 11, 6, 8, 9)