That smuggler team is viable, yes, but 3 of those will have very limited use after you reach div. 1. I wouldn't delay unlucking legendary characters to gear/farm Qi'ra, Vandor or L3.
For your JKR team I would recommend using HY or an attacker (Ezra) on offense, and using a tank (OB / GK) on defense.
For your CLS team 3P0 will make a great 5th.
For your Nute team g12+ Nest would be great. Droideka would be a good 5th if you're using Wat with your separatist droids. Otherwise, I've made ST Han work well on an alt of mine throughout div. 3 and 2, but he's underwhelming later on.