Migrating 20+ standalone production projects into a new GCP Org node -Gotchas/Things to keep in mind

I am looking to migrate 20+ standalone production GCP projects in a new Org node. Are there any Gotchas that i need to consider besides the special cases related to shared VPCs etc?   Also what is the advantage of using Cloud Identity (instead of Google Workspace) to setup the Org/domain or in general what benefits does the customer get by  moving to Org besides the added provision to setup Org policies, setup folders to define Resource Hierarchy etc. Below are some of the important questions that I have

1. Any pre analysis tools (like stratozone used for on-prem migrations)  that exist to evaluate the potential impacts before starting the migration?

2. Would there be any service disruption while migrating  these projects?  (Note:- These are standalone projects that do not belong to any Org and goal is to move them under an Org Node)

3. Is this going to be a straightforward migration from the GCP console compared to migrating projects across Organizations? Do i need a migration plan etc?

4. Any Discovery Questionnaire for the customer?

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