Did the conquistadors find the north west passage?

Answer 1

No, and the Spanish "conquistadors" never looked for the Northwest Passage.

The Northwest Passage was the - mythical - passage from the Atlantic Ocean to the Pacific. The explorers who searched for it were primarily English. No navigable passage was ever discovered.

With modern icebreaking ships, it's SOMETIMES possible to transit the "Northwest Passage" along the northern edge of the North American continent, but this is more like sailing through the Arctic Ocean than a true "passage". It is rarely ice-free.