Hidden page and random permalink

Hi,
I was wondering if any of you could help me with a little problem. I want to create a few ‘private’ pages that only a client can access. I want to send them a mail with a direct link to access that page. I don’t want them to type any password or something like that. They only need that private link.

Now there are options to make a page or post private in wordpress. But that means that nobody can access it.

So my questions:
1) Is there a way to make a page/post hidden from any searches,sitemaps,category pages etc. but still accessible with the direct link
2) Is there a way to create random/unique permalinks for these pages/posts? For example https://www.mywebsite.com/client1-3xyvYlTg. Or even https://www.mywebsite.com/3xyvYlTg might work