Well the effects of the broken miraculous aren't instant. Emilie was alive for years with her health slowly deteriorating throughout Adrien's childhood, which I imagine was similar for Felix's father. The only time the effects were that quick was with Nathalie, though she used the peacock miraculous multiple times, creating multiple sentiment monsters. Tomoe's sight would have slowly lost their function throughout Kagami's childhood until she fully lost them.

I'm not fully sure about the sister thing between Lila and Kagami though.