Hi puggy,
My suggestion for developpement is of course a flash device such the 16F87x serie but for the end project PIC16c712.

PIC16C712 have 1 PWM (for your 10KHZ tone ), 4 channel ADC and 1k of program memory (wich it's really enough for your needs).

O.k these are not really the most cost price efficient but they have what you want to do your project fast.

regards.