Dotting, I love PrC optimization
The swift action supernatural "teleport" is actually works as though you used Dim Door, with all of the annoyances that come with that (like immediately ending your turn!), so keep that in mind. My GM let me take Dimensional Agility to use with it, but that probably isn't legal by RAW (since Dim. Agility specifies "casting" Dim Door). Ask your GM whether he reads Shift as ending your turn when you do it, and whether he'd allow Dimensional Agility to work with it if Shift DOES end your turn.
I actually did something similar in a very recent campaign, though my teleportation subschool conjurer was a Samsaran with decent Charisma (for contracting with Planar Binding spells), and Mystic Past Life for adding some witch spells (like Death Ward, Heal, and Resurrection) to her class list. (She was also the PC responsible for the Gate described here.)
You'll want to take Summon Good Monster, a feat which significantly expands your summon list, gives the listed creatures Die Hard, and has some pretty cool synergies with Magaambyan Arcanist (which raises your caster levels and eventually gives you an extra minute of duration on your good summons).
Obviously, I also took Augment Summons and I took Superior Summons, which is great for helping flood an area with lantern archons and weak but useful critters. You can get amazingly vicious results with 10+ lantern archons (a.k.a., the laser array) if there's a bard in the party.
Otherwise, I didn't take any of the feats like Moonlight Summons spells because I wasn't sure they were supposed to apply to all summoned monsters, as opposed to just creatures brought in by Summon Nature's Ally.
I guess by RAW it works with all them, but I believe by RAI it was intended for Summon Nature's Ally critters. You'll want to ask your GM.
I think the ____ Summons spells will be less valuable at higher levels, because your Summons will almost certainly be acting as support rather than offense.
Hope some of that helps.
Magaambyan Arcanist is a neat PrC.
A nice trait for you if you want to go diplomatic is "student of philosophy" which would put some bluff/diplo off int.
Collegiate arcanist on the PFSRD
Personally, I'm fond of the "shadowcaster" archetype. Might be a bit "evil-looking" for what you want, but I'm quite fond of it.
Well, you're not in PFS, and I'm of the mindset of "anything can be re-skinned", so it dont really mater to me. I'm starting my first campaign in a few weeks (as GM) and I've let a player re-skin hammers as "dwarven battle bread" (from the discworld series). So honestly, fluff dont bug me much.
Otherwise... "fate's favored" can be a fun trait, it boosts luck bonuses, shows you're favored by the gods maybe?
I LOOOOVE seeing PrC optimization it's so rare so I try to cherish it. I've also been spending WAYYY to much time on these boards.
Have you started to think about what extra spells you will take? They gain access to 10 spells from the druid spell list (1/level) to be added to their own, so it might be worth thinking about them.
I REALLy dont know the druid spell list well... there isnt much that I can think of for a wizard. Summon nature's ally (the higher ones) might be interesting, but I cant think of anything else.
What kind of GM are you playing with? I know quite a few that dislike summons because they really slow down combat/clutter up the board. Might be worth preparing strategies in advance or working out an agreement with your GM beforehand.
You actually get things at the proper spell level (so entangle would be at 1st), but you're limited to things 2 spells levels below your highest level. So for your first level of the PrC, you get a 1st level spell.
The spells that I remember taking with Halcyon magic were Speak With Animals (so I could talk to my summons!), Barkskin (this is an amazing AC buff - I was using pearls of power to cast it on the entire party), Lesser Restoration (never prepped it, but promptly got a wand), Freedom of Movement (this is REALLY good to have), Atonement, Commune with Nature (great recon), and Spellstaff (disjunction in a stick!).
I do not remember my 3rd level spells or my 2nd fourth level spell at all. Which means I probably never used them.
I never used Atonement either, but I took it because being a wizard with Atonement felt cool.
One class feature I REALLY like was the Intoned Recollection. I eventually left blank slots at every spell level because eventually it was only a full round action to fill them. I also made sure to get Blessed Books, since those are specifically super-durable, water proof, etc. - really taking advantage of Intoned Recollection requires you carry your spellbooks around, so make sure the spellbooks can't be trashed if you're fireballed or have to go for a swim!
Crap, didnt notice the "2 spell levels below" thing... iritating. But you are right about intonned recollection, it's basically a BETTER fast study. (sorry for the derail mogwen, I've been working on my own build)