Trying to understand camper leveling up

I know that initially the campers max out at level 7. I know that crafting amenities of a certain type (like natural) will increase that level for campers of the same type. I've done a level 3 natural tent and am currently working on the picnic amenity.

I think the campers have to be present at the unveiling. Is that true? So, if I have a natural type camper that is not at the campsite, they won't have their max level increased? Is there any way to increase it at a later date, after the amenities are built?

Or am I completely wrong about how this works?

All campers with the matching personality as the amenity will have their max lvl increased. You only need to have the camper present at the unveiling party if you want to give that camper the 5 hearts rewards after finish an amenity.

- - - Post Merge - - -

But I still don’t know how the 5 hearts rewards works, my guess is that the system randomly select 5 out of 8 campers to give the reward to but I could be wrong.

Thanks! That makes sense.