just to add to what
B2N2 had written for the second series of questions with regard to dynamic stability two factors come into play---
one is reduced aerodynamic damping -caused by the control surfaces working through a smaller effective smaller angle ----if you have a high TAS then your the sideways component of damping forces relative to the forward component is decreased as TAS increases. this best seen in an illustration
also the overall effectiveness of the control surfaces are diminished due to compressibility and flow separation therefore less of the stabilizing surface of a particular control or stabilizing surface--- Vertical stab, chines etc.. is aerodynamically available--
-with respect to static directional and lateral stability... it is also attributable to the higher TAS due to the fact that the amplitude of any directional divergences are lessened for the exact same reason as above A large forward velocity component relative to any sideways or upward velocity components about the vertical or longitudinal axis ...for a compilation of 'acceptable and unacceptable stability' I would recommend Hugh Hurt Jr's text
Aerodynamics for Naval Aviators and D.P Davies Handing The Big Jets
I'm sure I could have said it better
