With extenders, always make sure you have the same SSID.
Your router should have two MAC addresses (one for itself and the extender).
Can't see why the HP won't work with extenders. Maybe you have to enable PF as well?
I'd remove all Security (just to get it working or at least the basic), and have DHCP set to Auto (always a problem when people force IP address's).
Problem with different manufacters is that they have their own terminology for basically the same thing.
Like Billion - calling it Virtual Server, when good old Port Forwarding is known to everyone arrrgh!!!