If I attack using Jumpluff with the "Fluffy Barrage" Ability, can I do things like attach an Energy or play a Trainer between attacks?
No, you would resolve all effects from the first attack and then either perform your second attack or pass. You don't get to go back into the main part of your turn again.
Source: Evolving Skies FAQ; TPCi Rules Team (2021-08-26)

Relevant cards

Note: All applicable cards may not be listed below.
SWSH7_4
SWSH7_4