If damage that can’t be prevented is dealt to Stormwild Capridor, it doesn’t get +1/+1 counters for that damage.

If damage that can be prevented is dealt to Stormwild Capridor at the same time as damage that can’t be prevented, it gets +1/+1 counters for the prevented damage before checking to see if it dies from the damage that couldn’t be prevented.

If multiple replacement or prevention effects try to modify damage that would be dealt to a creature, the controller of the creature chooses the order in which they apply.