The same issue exists in AC13 -- there were some improvements made to the editing interface, but CW elements cannot be considered "interchangeable" with SF Objects -- you still need to punch an empty opening before placing the CW, the doors within CW cannot be scheduled with Door Objects, etc. And I haven't checked, but I would guess that the SF objects are not available from the AC12 Migration Library -- so hold on to those.
MacBook Pro Apple M2 Max, 96 GB of RAM
AC27 US (5003) on Mac OS Ventura 13.6.2
Started on AC4.0 in 91/92/93; full-time user since AC8.1 in 2004