SOAP 1.2 strikes me as really reasonable - it's a mature format with interop to several languages and has schema validation.

The inconsistencies you describe above are probably due to each org in the government implementing the common spec independently of the others, and introducing differences without even knowing. Documentation is key here, but as with any large system, there can be gaps.

It's really cool that you mapped it all.

And kudos to Brazil for creating a common computerized platform.