Your table definitions are generating errors... Please correct, test and repost.

Actually there is no need for the expense a splitter function in this scenario...

IF OBJECT_ID('tempdb..#FolderPath', 'U') IS NOT NULL
DROP TABLE #FolderPath;
GO

CREATE...

Here is a different version using Steve's test data set...
It makes for a cleaner plan and a lower lower cost estimate but I haven't tested against a large enough...

Neither DECIMAL nor NUMERIC are...

Why not simply create a single "Lineage" table that has Object_id, column_id & source_system_id?

I'm assuming that the "official source" for a given column remains consistent of course...

This article by Itzik Ben-Gan should put you on the right path... 

If the amount to data you want to keep is smaller that the data you want to delete, there is a trick that uses minimally logged transactions to do the...

Because it isn't...