How to send mouse and keyboard to Virt-Manager guest

I don't believe this is possible using Windows guests. I usually setup a Samba server on the Linux KVM host and then share a folder out using that to my KVM guests.

Filesystem Passthrough

The documentation on sharing a KVM host's directory with the KVM guests (Linux) is available here on the virt-manager website. The page is titled: Example Sharing Host files with the Guest.

Setting up Samba

The linux-kvm website also contains directions for setting up Samba. That documentation is available here, titled: Tip: How you can share files on your Linux Host with a Windows Guest using Samba.

I don't know how auto-resize in Virtualbox works, but I also searched for disabling clipboard sharing through Spice on my Linux system. Ivan Kozik's comment above pointed me in the right direction, but did lack some information which i had to gather and want to share:

1. You need to have libvirt package installed to use virsh.
2. Type in terminal: virsh edit NAME where NAME is the name of your guest. The Domain XML is opened with vim in your terminal. If you are not familiar with the commands, find yourself a cheat sheet.
3. Under <devices> find <graphics> and inside add the line
   <clipboard copypaste='no'/>. Save and exit.
   For further information search in their docs.
4. Restart the guest. And you will notice that the clipboard sharing is gone.