Pretty accurate guide, I'd say, I usually act almost in the same way. Sometimes, I believe, there are some other less risky ways, though.
For instance, when your foe has the team with Phasma leader or/and 2+ enemies who use to call for assist, it might be even more important to start with Dhaka instead of Sid. Especially if you have 2 or more jedies in your team. She is an easy target, and her stuns hurt, and great risk to miss attacking Sidious by your jedies, and risk to get Sid back... Up to you.
Personally, I don't have Poe, but if someone has, I don't see a necessity for them to begin with Sid if you start your battle with Poe's taunt. Sid is hardly to cast his Heal Immunity against Poe's tenacity, and actually who cares about that in Arena battle? You should start straight from the cannons: FOTP, Rey, Droids... Or even Dooku if you succeeded to expose him.
There is also some specific in GW. In this case I also try to left characters like Chewie or Barris for the end and it's better not to place Heal Immunity on them letting them heal themselves. Their damage is insufficient and while my damagers are slowly going through enemies' huge HP and self-heal with their ordinary attack, my healers do their work for future fights and reset their cooldowns.
