Am going to use the PIC16F1827 and the circuit needs a 32.768kHz crystal on the T1OSI and T1OSO pins. As it turns out the same pins are used for the clock and data lines of the In-Circuit Serial Programmer (ICSP) which will be needed as well. So I had to know whether I can have a crystal on the pins and still program the MCU via ICSP. I breadboarded a circuit and test shows there's no problem using the ICSP with a crystal and its capacitors on the pins.
However, I discovered that the crystal and timer1 will not work if the PICkit 2 programmer is left connected. Once removed the timer works fine.