2) Is it necessary to wait for the purple hero to appear in order to unlock the three tents in the starting areas? I spent some time trying to figure out this puzzle with the rusty, azure, golem, and medal heroes, but I couldn't find another solution other than waiting for the purple hero to unlock the path.
You can try it. No one is stopping you.
But if the purple hero arrives, he will also be able to unlock the path to the cross with the Grail.