What aerodynamic data (drag/lift curves) exists for the A-10?
Good luck finding number 1-3 on your list.  As far as I know these are proprietary data the you would have to get from Fairchild Republic.  After a career of flying fighters I never saw this data or really care about it.

In my opinions numbers 4 and 5 on your list are much more relevant.  What you are looking for are called EM diagrams.  EM stands for energy maneuverability and these diagrams show a scale of turn rate, turn radius, airspeed and altitude to display meanueverability at a given energy state.

Using these diagrams you can find some key performance factors:

Min maneuvering airspeed - where the rate and radius slope drops off on the left of the chard showing min flying airspeed at given altitudes and wing loading

Max instantaneous rate of turn - max possible turn rate given a certain energy state - top of the rate curve then drops off

Max sustained rate of turn - maximum rate that can be achieved while maintaining your energy state (Ps = 0)

Corner velocity - velocity to achieve max rate at a given energy state

Min radius - smallest radius of turn acheveable given a certain energy state

Radius for given conditions - important to determine this when planning something like a targeting attack

I've found an A-10 EM diagram and a good Mig-21 diagram that annotates the factors I have defined above.

Note:  I have to giggle at your "Low-Mach data is good enough for me" statement.  There is no high-Mach data in an A-10.  It will top out around .6 Mach (max speed around .7)

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