There is nothing difficult in your questions and some are basics
how to store passwords from wallets and exchanges
How are you usually storing other similar sensitive information? Who, when, where, can access the sensitive information (Which level in the company has access to it, janitor, CEO, CTO, etc...) Only related staff should have such info (a janitor doesn't have to access it)
The problem also misrepresented that the password can know a few employees
It isn't a problem. every company has a different access level, some people working in; have only a few passwords
I.E a community manager has the passwords of the social media accounts and blogs representing the company but will never have the password giving access to the general ledger or to any accounting related thing
In addition, bitcoin is not officially available and how do you officially buy it with investors ' money?
Bitcoin is officially available and can be purchased with maybe 20 different methods. A company would prefer to use a bank account over any method. Sign in upon an exchange sending a bank transfer, buying coins, and move the coins to the company wallets