When Fox Fire targets units with '4 Might or less' and those units' Might is increased above 4 before Fox Fire resolves, what happens?

Ruling: Fox Fire locks in its targets when cast. At resolution, the caster selects a combined 4 power or less from those previously selected targets to destroy. If no targets meet the criteria anymore, the spell resolves doing nothing (spells never fizzle in Riftbound).

Sequence:

• Fox Fire is cast and targets are selected (must be 4 Might or less at this time)
• Other spells/abilities can be added to the chain
• When Fox Fire resolves, the caster chooses which of the original targets to destroy, up to a combined 4 Might
• If all original targets are now above 4 Might, Fox Fire resolves doing nothing

Nuances:

• Targets cannot be re-chosen at resolution if original targets become invalid
• Zero is a valid number for "any number" effects, so choosing no targets is legal
• Ravenbloom Student triggered abilities only go on the stack after Fox Fire fully resolves, so they cannot pump themselves before Fox Fire resolves
• Fox Fire cannot target units on a different battlefield than where it was played if the original targets become invalid