The Scaling upgrade complements other upgrades and covers different aspects, such as advanced strategies and tools to streamline scaling efforts. While some foundational elements might overlap, the content is designed to expand your implementation options, not duplicate them.
Regarding tools, you can absolutely use LeadPages instead of GHL for creating sales pages. Both tools work well for this purpose, though GHL offers additional integrations specific to scaling.
Choose what aligns best with your current setup and preferences. If you have further questions, let me know!