Ok so I did it, 7 starred BB8. I also believe I did it with bare mininum First Order team. Here is my toons so you can compare yours
Now some of you may laugh but I got BB8 on my 117th try today and after was also able to 1 star the mythical.
Hopefully this will help anyone who's FO team is subpar.
1. First Order Officer is your boy. What I made sure is that every chance I got, I used him to decrease Fin's turn meter.
2. From there, I targeted Rey used specials on her until she was gone.
3. After that, I took out Chewie. This worked because he kept stunning me and when Han attacked my toons would counter
4. Chewie and Han would end up both being in the red and I would use Kylo's aoe to finish them off.
6. At this point in both battles I had Phasma (leader left), a badly **** FO and Kylo full health. I was able to basically spam Fin to death with specials from there.
7. Once Fin was down, all I had left was a **** Phasma and Kylo just under full health. My first attack with Kylo I used his regular attack to get debuffs on BB8, had one attack with Phasma before BB8 killed her and then just spammed the hell out of Kylo's specials.
Now I will say out of the 117 tries, I had aquired gear for my toons, so more than likely if you have your toons at the gear level I have mine and decent mods, you will get it done in a few tries.
Hope this helps some people out there!