I don’t like the term “filler name” for a reason… it seems to diminish what could be a honor name for someone. My middle name is Lɛɛ honoring my Papa (mn: Lɛɛ) whose name honors his grandma (mn: Lɛᴀ pronounced Lɛɛ). I’m honored to hold the middle name due to its history. If the fact that it is a popular “filler name” is the only reason you don’t want to choose it, I think that, as long as your child knows the history of and your reason for choosing the name, you should reconsider it as an option.
On the other hand, you might consider [name_f]Kirrily[/name_f] as an option.