While IIR notch filters are attractive, I need to retain phase linearity at the filter output. I imagine that it's possible to use a standard IIR notch filter: https://www.researchgate.net/publication/224174145_A_Complex_Adaptive_Notch_Filter followed by some form of phase equalization. An alternative would be an FIR filter with conjugate symmetric coefficients. I am unaware of any FIR designs in the literature explicitly for a single complex tone.
Any thoughts on the best way forward?