I can confirm that this happens for me as well, but it only seems to occur when I am using Remmina. I thought it was an issue for either freerdp or remmina, so I have been attempting to build the newest packages of those applications (wip). The screenshots above are exactly what the cursor shows up as whenever moving into a windows rdp through Remmina. Vinagre works fine, but it doesnt attempt to change the cursor from the default Breeze cursor.

I am not sure that this is published under the GPLv2 license. I can't find anything on their site that says their tools are GPLv2.

I am not sure what the current status of adding this to Software Center is, but you can install VirtualBox by following the instructions on the Solus wiki.