How to copy all values of a characteristic (AUSP) to another

Hello experts,

I need to re-organize a class (TC CL02) used to classify change masters (TC CC01, ...).

The class-type is "025", the classe name is "CHANGE02" and the characteristic is called "category" [CAT].

The goal is to

1. create a new characteristic value "old category" [CAT_ARCHIVE] and assign it to class CHANGE02 -- DONE
   
   
2. copy all values within the classification of each CHANGE02-classified object from CAT to CAT_ARCHIVE
   ==> How do I do that? Is there a transaction or report that'll do the trick or do i need to use FMs. If I need FMs which ones?
   
   
3. Modify values CAT in all CHANGE02-classified objects based on a mapping / ruleset e.g. IF old_value == 5 THEN new_value = 99.
   ==> Ho do I do that? I assume a script is required and the write-FM would be that same as in "2.".

I did a lot of searching in this, on the SAP network, and elsewhere but did not find a clear approach. LSMW was mentioned, even right out table updates and inserts - which I'd be fine with but it seems somehow "unclean" to just go for it like this.

Your expert input is highly appreciated!

BR

Ben