No it does not kick off Lux by itself but it is relatively simple to double click the Lux icon and open the .lxs file generated by the exporter.

Not sure what you have going on with the materials. All I had to do was select one material and use the automated conversion to build the rest. I haven't had any texture issues. Not having any problems adjusting materials on this end.

I'm on a Windows 64Bit workstation with 32Gb RAM, current Luxrender stable release, DS 3.1.2.32

This is an alpha project at this point so some variances bewtween user results are to be expected.