Without probe Droid, I'd say:
HK, 88, bb8, T3, and either R2 or L3.
Bb8 is a must because that 40% starting TM is too good to pass up. 88 combined with T3's Zetas makes for a powerhouse attacker. T3 is going to be your only option for dispels though, and even then only defensive buffs. If you have BB8's healing zeta, I'd probably favor R2 over L3.
Of course, that squad would only work with at least 4-5 Zetas on it, so it's not a cheap squad by any means.
Adding in probe Droid over R2/L3 is my ideal linup for all the Target Lock synergy between IPD/88/T3. I'm hoping for a target lock synergy being added to HK's passive, but that's probably a pipe dream.