Feel free to add any comments, since this just based on my personal experience
Functioning as a team: As usual, try to stay in 1 or 2 groups, as there are quite a lot of guards, and the game mode is almost 70% guard spam. Try to keep on eye on the hecking invincible, since that thing is horrendously fast for that obese monster.
Hornet: I feel that a sniper playstyle more fits the hornet, as it lacks to DPM to mix with the guards. It might be best paired with the Cerberus, though I can't verify that. Instant reloading is useful for this.
Cerberus: As being a medium tank, it can do a lot. Can mix very well inside a scuffle with the guards, while still good enough to snipe those pesky rabbits and hedgehogs.
Goliath: Seems to be best at the periphery of the guards, slowly smashing inwards. DO NOT try to reverse when the immortal is spotted. If you have the turbocharger-like thing, try to brute force your way past the field. Reverse will doom you.
That's is all I have for now.