With Okta you federate the 'Office 365 tenant name' (which is the default Microsoft domain you have) or the 'Office 365 domain'?
Solution: You federate with Okta only the 'Office 365 tenant name'
When does Okta bring LDAP groups into Okta?
Solution: During both LDAP import and JIT
When using Okta Expression Language, which of the following will have the output: okta.com
Solution: String.substringBefore("abc@okta.com", "@okta.com")