Hello Mary,
As your question below, normally we never use report area 14 for booking any transactions in SAP. So, I believe that it’s no impact for maintaining any depre key in this area.
However, we never change data in this area before, so please do the same (just left the depre key the same as it’s default, no need to change it)
And asset class for CI signage , we agree as your clarification & process below, but please ensure that depre key will be updated to YTT2 (corrected useful life for CI signage)