Having notes appear in all contacts for that account? (and 2nd Q about user access)

Having notes appear in all contacts for that account? (and 2nd Q about user access)

Hi guys,

I met with two contacts and would like to have my meeting notes appear under that account, so that whichever staff member I access within that company, those notes appear.

Would I be best to enter my meeting notes under Accounts to achieve this?

Otherwise, what's the best way to have contact notes appear for all contacts within an account?

Also, I have imported my contacts with lots of fields that I'd also like to appear under each contact's account. They were mapped to the Description field but the contents do not appear under Description in that contact's account. Can this information be shared between the two modules?

The second question I have is how to restrict access to contacts/accounts with a specific lead source to other users.

Thanks in advance
Jo