If my bluray player has a USB output, can I connect it to my laptop or HP touchpad for Netflix, etc?

Your usb port is only for input devices, to play external videos, music, and pictures.
If its Sony, it could also be a usb wharf for the wireless interface thats not included with your appliance, simply can be purchased through sony.

I believe all your devices can individually run netflix, so there's no need for syncing any of the tendency. Your bluray player should have netflix already preloaded. Your HP laptop, simply download microsoft silverlight to stream off netflix.

The HP touchpad on the otherhand run HP's WebOS, which right now does not have an application for netflix.

The sole way you could spawn it work, is probably rooting your device, and run Android's ORIFICE.

I hope your question is answered.