If I qualify as a Level 2 Professional Trainer for all 5 modules what happens when I become a Level 1 Lead Trainer?

Any Level 2 module you qualified for as a Level 1 Professional you will still be qualified for as a Level 1 Lead with the addition of being able to contract that module with KRI.

So if you qualified as a Level 2 Trainer for all 5 modules as a Level 1 Professional, you will be immediately qualified as a Level 2 Lead at the time you become a Level 1 Lead.