You would not need a lawyer for simply using info you found in the public domain. Trading on insider info can be completely legal or illegal - here is how the SEC defines it:
Illegal insider trading refers generally to buying or selling a security, in breach of a fiduciary duty or other relationship of trust and confidence, while in possession of material, nonpublic information about the security. Insider trading violations may also include "tipping" such information, securities trading by the person "tipped," and securities trading by those who misappropriate such information.
No if you trade on insider information, whether it's for your clients or for yourself, you will be prosecuted. http://www.reuters.com/article/us-comcast-hldgs-insidertrading-sec-idUSKBN15P2KA This guy was just trading for himself, still got into trouble with SEC. Hope the guy has a good lawyer.