1. Do I disable Google Sync services (gmail, cal, and contacts) and replace it with Flock?
2. Is my contact list and cal events empty until I enter a password to unlock them?
2. The Flock encryption is used for transmitting data to/from the server. On the device, we let the Android permission system take over from there, so you don't have to enter a password in order to see your contact or calendar items. Your workflow remains the same as before.
Feature request: Please support contact checkpoints. Some app accidentally deleted all my contacts once, and the only thing that saved me was Google's "restore contacts as they were X time ago" feature.