@Astrodude55 , mid R2D2 for all offense then health then protection on that team. Don't even worry about speed. It's actually a good opportunity to use some nine-speed mods.
R2 will be there just for the stat boost. His smoke won't matter because if your opponents have gotten around GK's taunt then they've gotten around smoke screen. Burning is actually decent special damage at relic 7 all offense mod. I would rather let the stat boost help the real damage dealers of the team though, Ahsoka and JKA. So if you plug R2 in there, my advice is not to mod him any different than what he should be there, a stat booster for the rest of the team.