I see various D&D events listed (in particular Baldman Games). Will there be any D&D events created by D&D just for Gen Con or based on new releases (for example, Ghosts of Saltmarsh)?

Hasbro/WotC has no presence at Gen Con, and does nothing to promote their games there.  They leave it up to 3rd parties like BMG, who has its own line of AL compliant modules.

Coming to the event list soon (probably closer to the end of the month) will be a special Adventure League D&D called the Open that should be based on new releases. It is being put on by Sour Lemon Games out of Indy. More info will be available after its premiere at UK Games Expo on May 31st.