Yes. You must register your orgs with Conga Push Upgrade individually.

Yes.

No. It would help if you had a System Administrator profile to register your org with Push Upgrade.

Yes

It provides full access to users with a system admin profile for the new and updated components as part of the upgrade.

Conga Push Upgrade handles dependencies with Conga published packages.

Yes. Conga Push Upgrade can handle dependencies with non-Conga packages. Currently, Conga Push Upgrade handles the installation and upgrade of Adobe Sign (non-Conga package) for the latest Conga CLM (Conga managed package).

No, Conga Push Upgrade uses the OAuth mechanism that authorizes the Conga Push Upgrade system to access the given org through the exchange of tokens.

Conga release managed packages of an org should be on Spring ’17 release or later.

Please contact the Conga Technical Support team and raise a case for the issue. 

Yes. You must re-register your sandbox after refresh.