Sneaky/Support Binder Advice?

[Togath]

Anyone have advice for building a sneaky/support focused binder?
She's for a vampire/undead hunting campaign, and all WotC sources are available(including the online vestiges), other than BOED and BOVD and Dragon Magazine.
Race is human, and she has stat rolls of 13, 13, 13, 15, 16 ,17.
I was planning a dexterity focused build, and going full binder.
The GM has mentioned that the most common three creature types will be undead, outsiders, and elementals, in that order, and that there will be no shops, excluding a mage-smith who can upgrade items we find or ones possess at the start of the campaign.
Starting level is level 7, with 17,000 gold and/or gold worth of items.
HP-wise, it's max at first level, and rolled thereafter(already rolled, got a result of 35).

Currently, Paimon, Malphus, and Tenebrous look like useful/interesting vestiges.
edit: nearly forgot to mention; the Binder's alignment is neutral good.

[Mnemnosyne]

Don't forget to look into Acererak as soon as you can bind him (should come online at 8th I think it was) for his own undead advantages. Hide from undead at will is awesome, and his paralyzingly touch is solid against things it works on. Kas will also allow you to score crits on undead, and even blind them.

Tenebrous is indeed awesome for the infinite turn undeads, but would be even better if you stopped being good and decided to be neutral instead, because then you can choose whether to turn or rebuke each time you bind Tenebrous. And rebuked stuff stays rebuked forever, even after Tenebrous expires and you bind someone else.

Dahlver-Nar has a very interesting use in that if you use his shield self ability, if your target fails their saving throw, you can damage them regardless of what other protections they might have. Let your party rogue sneak attack you and half the damage goes to your enemy. Just make sure the half that goes to you can't kill you. It's niche and probably not the greatest idea in general, but in a few circumstances it can let you damage things you otherwise would have a real hard time hurting.

It's not what you were aiming for, but if the appropriate situation comes up, remember that Andras is basically a mounted charger in a can. You get a horse, a lance, and proficiency to use them, along with a solid ride bonus. If you get your own valorous lance, and you have power attack, it makes it even better.

Speaking of which, too much dex focus is probably a mistake. While you can get a little precision damage, and thanks to Kas, even apply it to undead, that's still going to be inferior to power attacking with a nice two hander, I do believe. Also, Paimon boosts your dex already, and you have to keep armor in mind, since ideally you'll eventually be wearing pretty heavy armor. So max dex will probably come into the picture sooner rather than later. Remember that wielding a big sword doesn't really prevent you from being sneaky, especially when you have abilities like invisibility, etherealness, and Mindsight at your disposal to keep out of sight and know who to avoid.

For support, don't underestimate Focalor's aura of sadness, especially the -2 to saving throws. That makes it easier for you and others to land things that grant a saving throw. Chupoclops offers a similar aura, and since the penalties are untyped, they stack, but you won't be able to bind both of them until 14th level, since once you're 10th one of your binds should be permanently assigned to Zceryll. Speaking of which...

Once you hit level 10 and have access to Zceryll, I would suggest going knight of the sacred seal of her. Especially if you're going to be meleeing and getting into direct combat, the proficiencies you get from that prestige class are excellent, since you lose no binding progression. And it's not like you ever want to not be bound to Zceryll once you have access, except in rare and unusual circumstances.

Also, in case you don't have them handy, my favorite binder guides, including my own guide to your summons once you have Zceryll:
The Consolidated Binder Handbook (http://brilliantgameologists.com/boards/index.php?topic=11235) is still my favorite general binder guide, because none of the more recent ones have been updated fully yet.
The Binder Handbook (http://http://www.minmaxboards.com/index.php?topic=2942) is less complete, but has useful information nevertheless.
The Binder's Summon List and Spellbook (http://http://www.minmaxboards.com/index.php?topic=9094) is my own guide which will become relevant once you reach level 10 and can bind Zceryll.