I honestly have no idea how to do the Governor’s Favor.
For the Freemasons, you should have a good relationship with Saint-Chapelle as your quaestor; it’s been a while, so I’m not sure if you have to be French too (although I imagine being literate would help).
If you’re strength-focused and get Samantha to let you execute Calkin (the spy in New Orleans), you get a chance to drink his blood instead of simply tying him down and waiting for the sun to rise.
You get an option to feed on Marie Laveaux as long as you stay in New Orleans. You get to feed on Jefferson Davis shortly before you meet Silas. You’ll need to be a Southerner and to meet with Nathan Forrest in order to feed on him.