For those interested, looking at the logs it appears to poll the cloud every 15 minutes, but some clarification on this and answer to the other points would be helpful.
Correct, the sync interval is every 15 minutes.
I recall talking about making this configurable, but we did not expose it in the UI yet as we were cautious not to overwhelm the cloud services as you speculated. So, might be at a config file or DB level. I will check into that and likely contact you directly.