1. You can create unlimited number of layouts, the "projects" can create only 3.
The project is similar to the category that contains the layouts to the project, you can issue a maximum of 2 editing access.
2. No, all layouts are saved for life and their backups are not required.
All restriction free pygmy can be found here: https://www.figma.com/pricing/
From the core:
• A maximum of 2 editor
• 30 days to store the history layout
• No team component library
• No control over the transmission links and no private projects.
To pay for Figma only when working on a project team.