my Osmo Mobile 2 finally arrived today! After my bad experience with the Osmo Mobile 1 + iPhone 8 combo, which was "jittering" a lot, due to optical stabilisation of the iPhone 8, I am now quite happy with the results from the new Combo. The iPhone SE has no optical stabilisation. The added motion range of the Osmo 2 is also a clear improvement.
But see for yourself. Just normal walking, no Ninja walk etc.
My Conclusion: I can recommend the iPhone SE, the last one wihtout optical stabilisation, for the Osmo Mobile.