I modified the top to make room for an installed female header. This includes making the gap then adjusting the lower wall into a structure that pressed close to the installed header and the header used for the Seed itself. It's a little tighter of a fit now so it all stays together a little better :) To the bottom portion I just added the pegs from another model - https://www.printables.com/model/729521-daisy-pod-snap-fit-case-for-daisy-seed - it lined up perfectly with this person's model so it was an easy thing to do.

You'll have to re-orient the top in your slicer, otherwise nothing much to do but print the pieces. I didn't include the button caps because I'm using the ones from the original model.