Migrating Page,Block and Media-Models to a multisite solution.

Hello,

Currently at the start of a project where we want to migrate a stand-alone episerver site (source-project) into a multisite solution (target-project). Now the source and the target-project have a contenttype for GenericMedia that has the same ContentType Guid. Im assuming this would be fine, the target project has the same filetypes + some.

We do however have seperate models for Image, Audio, VideoFiles in the source project. In the target project these either map to their own Image- or VideoFile model with a different Content-Type Guid than the source project and in the case of AudioFile it's filetype maps to just the GenericMedia type in the target-project.

Looks like this:

Source-Project:

GenericMedia : MediaData (Guid0, ExtensionString = "pdf,doc,docx,zip,xls,xlsx,ppt,pptx,txt")

AudioFile : MediaData (Guid1, ExtensionString = "mp3")

ImageFile : ImageData (Guid2, ExtensionString = "jpg,jpeg,jpe,ico,gif,bmp,png")

VideoFile : VideoData (Guid3, ExtensionString = "flv,mp4,webm")

MediaFile : MediaData (Guid4, no ExtensionString)

Target-Project:

GenericMedia : MediaData (Guid0 (same as in source), ExtensionString = "pdf,doc,docx,zip,xls,xlsx,ppt,pptx,txt,crt,geojson,json,kml,eps,mp3")

ImageFile : ImageData (Guid5, ExtensionString = "jpg,jpeg,jpe,ico,gif,bmp,png,webp")

VideoFile : VideoData (Guid6, ExtensionString = "flv,mp4,webm")

Im thinking that given that the same extensions/filetypes maps to a contenttype with a different GUID in some instances that it could be a problem. Our plan to migrate the data was to use the Export/Import tools under admin once we have migrated all the code. But Im uncertain how we would handle the cases above. Is it possible to change the content-type guid manually in the database so that for example the ContentType Guid of the ImageFile in the source matches the target (assuming props are the same) or would that be hard/potentially lead to problems?

Or what would happen if multiple datatypes has the same Extensions?

Looking for ideas or anyone who has had a similar issue to solve before?

Thanks!