Tm4C123 I2C sensor library control issues

I am developing code on the TM4C123 processor using the launchpad with resistors removed that would interfere with I2C operations. 

Code Composer Studio  Version: 5.5.0.00077,  TivaWare_C_Series-2.0.1.11577.

My project uses both I2C0 and I2C1 and is working fine with external pull-up resistors.  Here are my questions.

1.  Using the sensor library (preferred as it is the basis of my working project), can I detect a NAK event from my external devices?

2.  The library appears to preset the clock to 400Khz.  Can I set that to 100Khz?

3.  Can I set weak pull-ups on the I2C0 and I2C1 port pins (see setup code below)?  I need to use these functions without external pull-ups if possible.  Even if this can be achieved, the value may be insufficient to meet timing specs but it would help to know if I can enable weak pull-ups on the pins or not.

Here is the IO Init code for the I2C modules:

#ifdef USE_I2C0
    SysCtlPeripheralEnable(SYSCTL_PERIPH_I2C0);
    //
    // SCL0 - Enable pin PB2 for I2C0 I2C0SCL
    //
    GPIOPinConfigure(GPIO_PB2_I2C0SCL);
    GPIOPinTypeI2CSCL(GPIO_PORTB_BASE, GPIO_PIN_2);

    //
    // SDA0 - Enable pin PB3 for I2C0 I2C0SDA
    //
    GPIOPinConfigure(GPIO_PB3_I2C0SDA);
    GPIOPinTypeI2C(GPIO_PORTB_BASE, GPIO_PIN_3);

#endif

#ifdef USE_I2C1
    SysCtlPeripheralEnable(SYSCTL_PERIPH_I2C1);
   //
    // SCL1 - Enable pin PA6 for I2C1 I2C1SCL
    //
    GPIOPinConfigure(GPIO_PA6_I2C1SCL);
    GPIOPinTypeI2CSCL(GPIO_PORTA_BASE, GPIO_PIN_6);

    //
    // SDA1 - Enable pin PA7 for I2C1 I2C1SDA
    //
    GPIOPinConfigure(GPIO_PA7_I2C1SDA);
    GPIOPinTypeI2C(GPIO_PORTA_BASE, GPIO_PIN_7);
#endif