Hi,
1) We've been using the libiio together with the IIO scope application using the remote backend on various laptop and desktop computers with different Linux distributions. So there shouldn't be a problem using in on other Linux systems.
2) It is possible to both read and write data to/from the ad9361 converter. A simple example application how to use the libiio to write data can be found here. If you are using the iio-scope application you can also load a file to transmit in the FMCOMMS2/FMCOMMS3 tab by setting the "DDS output mode" to "DAC buffer" and load the file you want to transmit.
It is possible to read and write properties like the sampling frequency, etc using the libiio. The libiio contains a small exsample application that reads all attributes of a device and displays them. Writing a attribute is similar to reading it just use iio_channel_attr_write()/iio_device_attr_write() instead of iio_channel_attr_read()/iio_device_attr_read(). For a list of all the available attributes and their function check the AD9361 Linux driver documentation.
3) We'll check with MathWorks and then get back to you.
- Lars