The important thing isn't the place where you arrive, but the path that you traveled to reach it. Here you showed us that very well.
Now, remember that Nirvana is interpreted as "what is not". That means that your destiny is marked by your mental state and not by what delimit the concepts. You say "the round stone seems to mean the way to the Nirvana", but in reality it is only a clue, the first step, so that you yourself reach the Nirvana, the mantra, the inner and absolute peace.
The old man in the stone is the doorman, he isn't there by mere caprice or chance. If he let you in, you're a lucky man. The cats, however, are the guardians of peace and moderation. You say they didn't leave when you approached, don't forget that this is their territory; there you're the foreigner, why would they go away?
And for those who are afraid of the old man with the beard, I say to you: don't fear who opens the doors of your destiny, because the locksmith who forges the key to that door is yourself.
Thanks for sharing @slowwalker
Thank you so much for your thoughtful explanation and interpretation.
Your words make me more clear on that I had seen at the temple.
Thank you again
And I am very grateful that you have shared your trip with us.