I think the debuffs order it's the same method as any other games with interaction of character A and B

A Ability (whatever debuff) > A Passive > B Passive > A items

In Naruto Online case

Mystery (whatever debuff) > Chase (passive) > Passive from Main.

Jonin Minato case

Mystery (tag) > New Passive (Paralyse) > Main Passive (Poison Tai).

It's pretty obvious what will hit first by description of each Ninja.

Another example when you use Neurotoxin and Poison Tai. Neurotoxin applies first by passive order.

It's obvious when u vs a reflect ninjas, neurotoxin got reflected first, but poison tai applies