Sonds like a fun project and a good tool, it looks like you will be able to use it much more then more "toy"-ish sax or flute. I personally would get it!
For perfect pitch/musical training I am using some materials I have, and I also tryingto create some additional ones. Some activities I have already been doing, some I’ve seen other Home schooling parents do.
We use guitar, xylophone and electric keyboard ( we do not have piano right now, as we were traveling a lot). I do need to get more consistent, but I am also working on making some lesson plans so I can start on more consistent training within a month or so.
So far we did a lot of classical music listening, my husband plays some classical guitar for her and she watches and trying to copy or uses her little drum or bangos for rhytm, she loves that.
We have some audio files with recorded notes played, following with the child guessing the right note ( part of the program we have), I usually put it on as she has her independent play, so she can hear it o the background and she really pays attention.
Then we have a series of audio files that were specifically created for teaching young children perfect pitch, however they are done in Russian ( which is great for us, since this is one of the languages that she learns). But the main principal is that she is listening to a simple melody song, or action song sang by a child, then the same song is performed with the names of the musical notes ( do, re, etc.) instead of words, and then the third time the same song is performed with additional percussion instruments with no words, so child can join in and use his/her own percussion instrument ( thus rhytm recognition and training), some songs are dome as action songs ( so when the child listens to the first version they can do some action with parent ( but she is still too young for that so we just listening)
I am planning to add also some LR files to this system, just thinking on that these days.
Then we also show her some LR files with instruments, musical notes; Trebellina for entertainment. We also have another program with different musical instruments , EK about them and how they sound (in Russian) we started on that and she likes that.
I am planning to make flashcards with musical notes and combinations, have not done it yet though. The use the flashcards in combination with our keyboard and xylophone.
Oh yes, she also watches some clips of young children performing different classical pieces on various instruments and we take her to see some live performing sometimes, and explain about different instruments
These are just some tips, hope this is a help.