I assume it's similar to Trace of Two Pasts. Aerith & Tifa is actually interacting while telling their stories to each others.
Not sure if Cloud would be that opens to Zack. But there's a time when Zack treated two infantrymen along with Cloud for them looking after Cloud, maybe they ask about Zack's life and he shares his childhood story in Gongaga jungle. I imagine he loves camping with Sotetsu. In return, when Cloud invited Zack to have dinner with his mom, Claudia perhaps also tell Zack about Cloud's childhood.
Though, what I want is the 9 months on the run. I know it'd be one-sided since Cloud doesnt respond, but it's a good bridge to Part 3.