iio lib command line for daq2 design (AD9172-dac-emz) with zcu102 (rev 1.1)

I am unable to use the hdmi driver on the ZCU102 (Rev1.2) using the reference design daq2 on zcu102 (2021-02-23-ADI-Kuiper.img). Hence, I am trying to use iio command line tools running on zcu102 via serial (COM4) teraterm. Here the iio_info returns with 4 devices in the first line of the output). However, I see only three devices listed subsequently (device0: ams, device1: hmc7044 and device2: axi-ad9172-hpc). I have some questions about this:

Q1. Is there a missing 4th device not listed in this?
======= Start - iio command line log ===============
root@analog:~# iio_info | grep device
IIO context has 4 devices:
        iio:device0: ams
                1 device-specific attributes found:
                No trigger on this device
        iio:device1: hmc7044
                7 device-specific attributes found:
                No trigger on this device
        iio:device2: axi-ad9172-hpc (buffer capable)
                No trigger on this device
                2 device-specific attributes found:
                No trigger on this device
======= End - iio command line log ===============

Q2: Can device0: ams be used to program registers on the zcu board using the iio_reg ? Where is the register map for ams device? I am specifically trying to program the dac_data_sel register. What is the command for this?

======= Start - iio command line log ===============
root@analog:~# iio_reg ams 0x0
Unable to read register: No such file or directory
======= End - iio command line log ===============

Q3: IIO vs ACE: What decides whether the DAC board SPI registers for HMC7044 and AD9172 ICs are programmed via the ACE sofware running on my laptop through the micro USB connection or the via commnand line on the serial terminal running on the ZCU102 board through the FMC interface.