The scavenger hunts will net you 6 friendship bracelets total.
Capture Them All
A single quest giving 1 friendship bracelet.
This quest can be completed once per summerfest event on each of your characters over level 50.
Pick this quest up in..
Sanctum /setwaypoint 7414 3142
Meridian /setwaypoint 6211 5202
It is available from the first day of summerfest and can only be completed once during the whole event.
Once you pick up the main quest you will then need to pick up all the smaller quests from the same NPC, one for each creature.. Make sure you have plenty of space in your quest log!
All the creatures you need to capture are in storm legion zones, they are clearly marked with yellow circles on the map..
Various quests rewarding merit badges.
Pick up in Meridian/Sanctum or Tempest Bay.
For this quest you need to fish up summer sunfish, you can also just have them in your bags and hand them in, so buying them off the auction house is fine.
When you port into any of the Mathosian or Storm Legion zones and open up the map, you will see blue fish symbols on water sources. These symbols mark the location of summer sunfish plants.
Fishing around these summer sunfish plants will give you summer sunfish and sunplant leaves..