Find standard code overlayering in Dynamics 365 FO

We are preparing for the code upgrade from AX 2012 R3 to D365FO 8.1, the latest version recently released. As you know it is extensions-only, meaning we are not allowed to modify any of the standard objects directly. I would strongly suggest to familiarize yourself with Extensions if you are planning to go down this journey as well. An important part of this is that you need to send in Extensibility requests via LifeCycle Services, for code that cannot be moved to a pre- / post-event handler. Our large number of customized methods came out well above 1000+ overlayered objects when we ran the LCS code upgrade tool on our modelstore. We had to find standard code overlayering of all methods to narrow down the search on what should be inspected for extensibility.

I have been exploring the options to use the MetaData API for extracting package information of methods. We wanted to find any methods, which belongs to both a standard, and a custom package, like ApplicationPlatfrom and ApplicationPlatform.JAD (our module). That did not lead to anything useful other than realizing that you can only access such details up to the root node level (table, class) currently. Here is the code piece for partial results: