Another thing to ask your GM about is Cell Directives.
They are kind of like Teamwork Benefits in D&D, but are (usually) better.
They can be found in each of the "Class" books; Daemon Hunter, Book of Judgement & Blood of Martyrs.
If you have Blood of Martyrs, and you can use Cell Directives, then Sanction Wardens on page 74 is awesome for you. Bad news is the whole team can only have one directive, and each one grants access to an extra list of advances and one special team ability, and the list for Sanction Wardens is pretty lackluster, unless you are going against a fair number of enemy psykers, then it's amazing. Good news is that while everyone else would have to pay 250xp, you wouldn't have to pay any (0xp for psykers) and the benefit is: if you roll on the Perils of the Warp table, an ally gets an immediate attack against you, and if they deal a wound, the power doesn't manifest and you don't roll for PotW.
Sanction Warden =
Be prepared to randomly explode at the beginning of your first combat.
Yep, don't have to worry about that anywhere near as much (assuming your allies can hurt you).
Beyond that:
(1) I have never liked any of the Alternate Ranks (or Background Packages) for Psyker either.
(2) You haven't mentioned your place of birth (Origins).
On #2: In order of suggestion, listing only the (relevant) good parts
Being from the Darkholds (Void Born) would get another +5 to Willpower, at the cost of Charmed. (Radical Handbook)
Being from an Imperial World would get you another +3 to Willpower.
Being Void Born gets you a 10% chance to not lose spent Fate Points, and lets you be the "backup" pilot.
Being Famulous Protégé gets you more money. (Blood of Martyrs)
Being Noble Born gets you more money. (Inquisitors Handbook)
Being a Hive Mutant (Hive World) could be *interesting*, since you can choose two minor mutations. (Radical Handbook)