ICSP is not dependant on defines, osc speed, or coding. The clock is generated by the programmer, and the micro is not running code while being programmed. ( In short, ICSP will not be affected and will work fine no matter what speed or defines you have)

There's many commands that are based on the actual osc speed and define osc has no effect. (pulsein and pulseout for example, the resolution is directly related to osc speed. the define osc is of no use for these)