So, Neanderthals were the last other hominid to survive...

...nope.

The Denisovans may have survived on certain Asian islands until as recently as 15,000 years ago. (Which also meant they had a quality that as far as we know Neanderthals didn't: They were seafarers).

Unfortunately, we're still no closer to knowing what they looked like. Which makes me wonder.

The Neanderthals generally buried their dead.

We haven't found a Denisovan burial site.

What if the reason Denisovan fossils are so rare and hard to find, and tend to consist of bone fragments when they do...

...is because they burned their dead.

Just an out of the box thought.