Advice Needed – How To Collect and Output Data Or Build "Profiles"

Hello, I hope I can find some advice here. We are wanting to build “profiles” of brands in our WP backend. A brands profile would be contained in a review page template, and we would input information such as what payment methods are accepted by that brand, and what countries they do business with, things like that.

My first question: where is the ideal place in WP to contain this information? Should we use advanced custom fields and a “profile” page template with custom theme design?

Should/could this be developed as a plugin to use on more than one site?

My second question is equally important, we would like to be able to call upon the data that is inputted for search/comparison/filtering. A user would be ideally able to search for a profile that accepts a certain payment method for example.

How is this best accomplished?

Third and final question: should this be done on a custom theme, or could we potentially modify an existing theme (say 2012) to suit our purposes – advantages/disadvantages?

I hope my questions aren’t too vague, we had this system half built in a custom PHP CMS but the developer never finished it so we decided to move the project to WordPress where there seems to be better and more reliable freelance talent available to hire to complete the project.