Vanilla XCOM: Overwatch crawl. LWotC: If you Overwatch crawl, you will be flanked by patrols, swarmed by reinforcements, and the mission timer will expire.
Before we talk about squad composition, stop thinking about your "A-Team." In LWotC, you have a roster of 40-50 soldiers, and you will need every single one. xcom 2 long war guide
LW2/LWOTC requires a much larger roster (often 40+ soldiers) because squads are tied up in multi-day infiltrations. Squad Persistence Vanilla XCOM: Overwatch crawl