See the SO link - it should be possible to define defaults if you want. One way would be to merge the defaults with each item in the list, but I think there should be a cleaner way too.
Is it possible to set attribute defaults in a list of objects? - #4 by jmdoman is another thread you could look at.
If you show an example of how the data structure you’re passing into that looks, someone might be able to provide a little more help as to how else you could do it.