1. When the Sanhedrin lit fires to signal Bavel,
Did Bavel then observe 1 day or 2 days of Yom Tov?
2. Later - when sh'luchin were sent to inform those outside of E"Y, did those places observe one day or 2 days of Yom Tov?
3. If they observed 1 day only,
How then could Y"T sheini be a k'nas for not making aliyah?
4. If the Sanhedrin would be revived, couldn't they resume signaling the World as it was before Kuthim or others interfered? EG on a secured Website or other system?
5. What was the nature of "v'attem minhag avoseichem b"yodeichem?". Was that a function restricted to not relying upon the "heshbon" or was it something else?