Would Battenberg ask the United States to let von Spee use the Panama Canal?

Could Battenberg invite the United States to let von Spee pass through the Panama Canal so the Royal Navy could intercept him?

No. American permission under those conditions would compromise US neutrality, so Battenberg would not propose it.

Allowing the German squadron through while British ships waited at the exit would make the United States complicit in the resulting destruction. The United States had no reason to agree, and Battenberg had no credible reason to ask.