Unusual encounters

[Windstar]

I was wondering something. Does it matter that you have a P5 and a P4 wizard in an unusual sighting? Or would 3 P3 wizards be the same? Is it just the amount of levels in a given encounter or what? And if it was just a total number of levels, would that impact the durability of the lesser wizards when the piper comes? Like if the episode was a success, would that dictate that the P5 and P4 wizards would have a better chance of surviving than each of the 3 P3 wizards, even if all were using the mirror image spell?