Magni should be OK with the M-100, but you might have background hiss and louder volume (so just turn down the volume knob, unless you get the channel imbalance from the potentiometer).
E09k is meant to drive higher impedance headphones so you won't get the magic #8 damping factor (headphone impedance / amp output impedance). A damping factor less than 8 makes changes in the output signal that are audible and the E09k's frequency response has a bass and treble roll-off according to Voldemort's measurements.
I'm assuming you meant the E09k when you mentioned the E07k, but the E07k has a low output impedance.
O2 works beautifully with the M-100 and has an low output impedance so you'll get well beyond the magic #8 damping factor.
What about the e11? Its all I got.
E11 should be fine. Many have reported it sounds good with the M-100's too.