He won't just take advantage of HK's lead, he'll give GG much-needed Hit Points and increase 86's critical chance even further. It's a no brainer for me... Jawa's gotta go. If you're not comfortable running an all-droid lineup, then keep JE in there. Personally I've found him to be underwhelming with an HK lead: His crit buff isn't really necessary with HK's leader skill, anything I stick his bombs to is usually dead before they go off and if he somehow manages to out live a droid and revive him, that droid is folded like a big check about two seconds later.
On defense, although I've seen the value of RG, I'd rather have 88 in the lineup because when he lands his AoE, he can usually get another shot. It would all depend on how much of a spong B2 turns out to be but droids weren't built to last - every build I've tried that has some sort of stamina fails slowly. I've had my most success by trying to end the fight in 4 turns. You'll know it yourself, with droids you know if you're going to win within the first 30 seconds...