Sharing the ICSP clock and data pins should not be a problem as long as they are used as outputs in your "normal application"

It might be a problem if they are used as inputs in your "normal application" as this means they are connected to the output of some other device which might be pulling the PIC pin high (or low) while you are trying to program it.

I think the resistors in series are just for current limiting and are not really necessary.
If you want to install them their values should be low in relation to the pullups on RB6/RB7 (if you use any)

rgds