I don't know the actual answer to your question, but I can share what I do know:
* Migrating from 2.x to 5.x without the help of Alfresco Enterprise Support will be a very challenging task.
* I believe that 2.2 was only released for Enterprise Edition. The suggested upgrade path reflects that we only certify upgrades from Enterprise Edition releases.
* The key lesson from the suggested upgrade path is that you cannot go directly from 2.x to 5.x, but you need to upgrade to the latest release of each major version (2.x, 3.x, 4.x, 5.x).
* This process is going to be time consuming and challenging, especially if you have customizations. If you go that route, you need to make sure to thoroughly test your system.
* My advice is to not upgrade the repository through all those steps. Instead, use a tool like TSG's OpenMigrate to export the content from the 2.x repository and import it into a 5.0.d repository. This will also give you the opportunity to improve your content model, content organization, and do other spring cleaning tasks.
Good luck.
Richard