I think the new standard in giving advice on clearing events should be to include characters AND speed. These events rely heavily on having enough TM on the final stage so that the "boss" doesn't blow you away with a cycle of uninterrupted stuns / hits.
The first time I cleared the bonus round it was very difficult and I had to run it a couple of times and purposely take more damage on stage 7 of 8 so that ST Han would be almost max TM when i encountered palp and RGs. If you don't have maxed out toons, your goal should be to manage your attacks on the last stage so that ST Han would be the next to attack. It's tough (took me 3 or 4 attempts) but doable.
Otherwise, you should switch up mods so that your toons have over 200 speed. I cleared the event on auto with:
Wedge (L): 170
Biggs: 180
CLS: 231
Leia: 233
Lando: 149
These speed numbers are 60 - 90 over base (except Lando +34), so admittedly tough to achieve, but if you can come within 20 speed less of these you should be able to clear it no problem. Otherwise, you can use this as a target speed to achieve for future events.
Hope this info helps in the future.