I assume that the inability to read several discs is just a software lack.
No, HD-DVD uses a different frequency laser. A DVD/CD player doesn't have the required hardware.
There were a few Blu-ray drives that could also read HD-DVD. I have one, the LG GGW-H20L.
The GGW-H20L is the most known one.I have a GDR-H20N, which is said to have the hardware for HD-DVD. But it is not sure.
I wish that HD-DVD is still being sold for archival purposes.BluRay and CD are fragile to damage due to their unsuitable data layer position.
Yes in theory. Both BD and HD-DVD use 405nm laser diode.But the chipset inside your drive may not support it.
A firmware patch could enable HD-DVD and WiiDVD on normal BD drives.