I finally got Chewie 7* !!!
My team when I pulled it off:
Boba g8 (L) / Embo g12 with zeta on his unique / Jango & Aurra g10s / Bossk g11
1. I put my absolute best mods on them focusing on speed & survivability but I did not leave out the areas each character needs. For example aurra & jango need offense & potency / embo needs cr.ch etc . Embo was my slowest at 191 speed & bossk was my fastest at 240sth.
2. I had omega's on some abilities not all - just saying - Boba being my worst & embo my best. Also all my guys were lvl 85 except boba being 80
3. I have a zeta on jango's lead but it didnt help at all. Boba's lead on the other hand helped me because I pulled off the contract fast & that gave me a chance. So if you go boba lead focus all fire on solo first
4. In my experience the biggest troublemaker was chewie followed by solo. When you successfully take these 2 down it becomes a lot easier
5. If you dont have dengar (like me) restart if when you get to play (1) your first target is under stealth (2) bossk is stunned .. btw I have no idea how tier 7 can be pulled of without bossk
Now to comment the event. This was absolutely the worst experience I've had playing this game. I had tried the last tier 200+ times and the problem is that it relies so SO heavily on RNG. I think the design was really bad and the requirements were honestly too high. As a result the last tier is not fun because the odds are so against you. One could have a full g12 BH squad and still get a plate full of ****.
Disclaimer 1: My comment above is not from my experience exclusively but from what I've heard from the whole community (at least the ones that have tried tier 7)
Disclaimer 2: A handful of people that breezed through it do not represent all the rest of the players that struggled. You could do some very serious work on your team and still not have a decent chance. So it's not people "not preparing" . It's the event