I participated in an online assessment of synaesthetics through some university (sorry, but it's been a couple of decades). They commented that in addition to the common forms, there are a number of more obscure variants. For me, colors have odors (at least many of them do, not all) and this is a less common variant. Sounds like your DD also has a less common version (but such a fun one -- let me assure you, some colors really don't smell good!).