Ok, I wanted to answer my own thread in case it helps somebody else.
a) to use virt-manager without password, you must use ssh-copy-id
And don't forget to add your user to libvirtd group on kvm host. (sudo adduser "username" libvirtd)
b) after consulting members online on irc, it seems that it's necessary to create one storage pool for each directory.
Only workaround seems to install virt-manager on kvm host directly. (not what I wanted so I will transfer my iso files in the storage pool each time I need to install a new OS)