What’s the default replication interval for Edge sync and what is the step to force replication?

When the Exchange Edge server starts, the Microsoft Exchange EdgeSync service starts and establishes a synchronization schedule.Configuration data is synchronized to ADAM once every hour.Recipient data is synchronized to ADAM once every four hours.
Steps to Sync Edge sync replication
Use the EMS to immediately start synchronization of data from the Active Directory service to the subscribed Edge Transport servers. Run the below command on the HB transport server.

You cannot modify the synchronization intervals.

Start-EdgeSynchronization -Server <Hub Transport server name>