If an account is public, then yes, you can see their posts, stories, likes, and comments on other public pages, but only what they’ve posted publicly. Instagram doesn’t provide the ability to secretly track a user’s activity outside of their public content.
A dry list of services definitely doesn’t work, especially for lawyers. Nowadays people trust not those who simply list “consultation, defense in court, contracts”, but those who immediately make it clear: “I know how you feel, and here’s how I can help.”