Finding users by a specific criteria

I want to create a website for multiple users to get together. I will be using the BuddyApp theme (https://themeforest.net/item/buddyapp-mobile-first-community-wordpress-theme/12494864). This, combined with buddypress plugin will allow users to create accounts on my website, share interests, pictures and so on(create a social page). When registering, I want to create a field besides the basic first name/last name/username/e-mail/password, a field called “hobbies”, where each individual will be able to write down one(or multiple hobbies).

The main issue is that, on the homepage, I want new users to be greeted with a search bar. On this search bar, they will be able to write a hobby(for example “football”), and after pressing search they will get as result a page with all the profiles of the users that meet the criteria(that have “football” as their hobby). When clicking on a specific individual, the user will be able to see his profile page.

How is all of this possible? More exactly, how to:
1) Create the extra field for users to write down their hobby
2) Create the searchbar on the homepage(maybe with autocomplete from a list of given hobbies)
3) Create the results page with all the users that match the criteria, in a sort of a list with their profile picture, username, and maybe an “add to friends” or “contact” button.

Thank you in advance!

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