OAuth client usage restrictions

[AppuSamy]

Does OAuth client needs to be published for every users to access Integration?

I have an OAuth client for API Integration. I can authorize my account with it and I can use APIs with it. But I want that client to be accessible for every user. I mean every Atlassian User, they may be under my account/organisation or they may be not under mine or they may be a standalone user. I want all of them to be able to authorize my client and use it. For that do I need to submit my app for review in marketplace or I just need to enable sharing in Developer Console App Distribution pa…

In addition to the above,

Is there any restrictions on the number of Authorizations or number of API calls in a month, for the publicly distributed client(not listed in marketplace)?

Also what if, I am working in a company like Google/Microsoft and I am trying to develop an OAuth integration and marketplace listing is not mandatory. Can I just make the client public and use it for OAuth and no legal issue will arise? I am asking this question, since no verification is done for the public client, only verification is done for marketplace listing.