Looking at this from kind of a sports angle, here's my take on the strategy.
Prime Wardens:
Haka has to neutralize Lagacy/force him to duel him. If this fails Legacy is too much for the other Wardens. You need Haka to actively neutralize Legacy.
Tachyon has to be kept off of Adept and Tempest, or from teaming up with allies to thwart a 1v1. You have a real hard time protecting anyone from Tachyon, and I would put Cosmic on it, light is as fast as Tachyon, so no reason he couldn't keep Tachyon from getting to adept.
Fanatic needs to take the fight to Wraith and take her out. Wraith is built for hit and run, Fanatic needs to find and eliminate Wraith as fast as possible.
Tempest needs to keep AZ and Bunker at bay. Basically keeping them busy until Fanatic can take out Wraith. Once Wraith is eliminated the fight turns to the Prime Wardens.
This would all be feasible if Adept can be kept clean ans allowed to buff his allies, bucause at that point the FV members can't match their opponents with that much boosting coming to the Wardens.
So basically, for the Wardens the 3 keys to victory are:
1. Haka keeps Legacy occupied.
2. Adept is kept clean by Tempest hodling off 2 people and Cosmic keeping Tachyon from swinging the fight.
3. Fanatic beats Wraith quickly and swings numbers their way.
Freedom Five:
The most dangerous Wardens aren't tough, you have to get on them and keep Tempest and Adept from dominating the field with their crazy powers.
You need to keep Haka and Fanatic from winning fights, both have the power to take out someone quickly.
If I'm running tactics for the Freedom V I want Tachyon going at Tempest and Legacy driving the fight to Adept to keep him on the defensive. Adept can't beat Legacy, and has to keep away from him. Tachyon has a better chance than anyone of dodging lightning bolts and getting to Tempest.
I would put AZ on Fanatic. She may be tough but ice should slow her down enough to keep her from taking anyone out. Wraith needs to work multiple angles. Helping anyone who needs it while staying away from the heavy hitters. You have to rely on her being able to handle evading Haka or Fanatic and throwing shots at Tempest, Cosmic and Adept too. Wraith is key to this fight, esp. in kiting Haka, because if you can Kite Haka Legacy is free to dominate the field.
Your real strength is how well your team works together. Bunker and Wraith keep projectiles flying and keeping the prime wardens on their toes defensively. AZ slowing down Fanatic. Keep Legacy clean to get a shot on Adept or Tempest, he won't need much to take them out. Keep switching up the threats to each warden so they can't take advantage of their strengths.
Freedom V keys to victory:
1. Kite Haka
2. Attack the casters.
3. Teamwork.
Prediction:
Keeping Legacy occupied is the key to the match, and the Prime Wardens fail there. Haka ends up being able to go after Bunker or AZ, and AZ slows Haka long enough for Legacy and Tachyon to get one of the casters gone. Haka and Fanatic end up taking out Bunker and Wraith, But Legacy and Tachyon take out Tempest and Adept, even though Captain makes it tough for them.
Fanatic and Haka with Cosmic helping can't match Tachyon, AZ and Legacy, even with AZ growing weak from his early work. AZ does enough to slow one of Fanatic or Haka and Tachyon jumps over to 2v1 whoever Legacy is on. Fanatic takes out AZ While Tachyon and Legacy take out Haka. At that point Fanatic takes out Tachyon and Legacy takes out Fanatic leaving Legacy and Cosmic. Which leaves the question: Can Cosmic fly fast enough to get away?