The confirmed unlock condition
The official Q&A states that Clone Troopers become available after a certain point in the story. It then explicitly says a full team of Clone Troopers is possible.
Story mission context
The same Q&A says Hawks is required on story missions, while skirmish missions allow any combination of Operators. Those mission conditions remain part of the answer and are not replaced by a generic squad recommendation.
What the Builder can do now
The Builder provides four standard planning slots and separates authored records from custom drafts. It does not simulate story unlock progress or enforce mission-specific deployment rules.