No one bothered to reply to this? That is sad. I don't know what your character creation rules/restrictions are outside of the non-paizo ban. However, what you are looking to do simply doesn't exist in pathfinder. Dread Necro was a niche pick. I don't know if you are still around checking this or if your game is a month in or what. That being said, one can make an arcane debuffing necromancer fairly easily. Whether it is viable or not is the hard part. Clerics and Oracles do it better, simply because they can spontaneous convert Cures to assist teams as a healer, or Inflicts for DPS, depending on alignment types. While wearing armor, with channeling on top. That's a win.
An idea for you.
http://www.d20pfsrd.com/classes/core-classes/wizard/arcane-schools/paizo---arcane-schools/classic-arcane-schools/thassilonian-specialist The Gluttony Sin Mage outright removes Abjuration and Enchantment spells from his repertoire ala the old edition banned schools. In exchange, you get to pick 1 spell for each spell level you can cast which is a Necromancy spell, and prepare it Twice. So you get double your Specialist bonus slot, it's just tied to one spell each level.
Make her an Elf, utilize this:
http://www.d20pfsrd.com/races/core-races/elf/spellbinder-wizard-elf to be able to pick 1 spell per spell level to be Bound and you can take a full round action to swap any spell to those spells as needed. Allowing you to customize your spells prepared a bit more, and between encounters shift some of the more utility type picks into battle spells if you feel you need more of them later in the day.
http://www.d20pfsrd.com/magic#TOC-Research-and-Designing-Spells Spell Research a better version of Mage Armor. 3rd level Greater Mage Armor +6 is a 3000 gp, 3 week, DC 26 Spellcraft and K: Arcana check which has precedence in 3.5 as a balanced spell. I allow my players to research a 5th level version for 5000 gp, 5 weeks, DC 30 Spellcraft and Arcana checks which grants +9 to AC. If the DM won't grant you spell research rights to get an upgraded mage armor spell, Bracers of Armor work.
Spell research a spell which follows like so, or something similar:
Dread Necromancers Touch
Necromancy, Level 5
CASTING
Casting Time 1 standard action
Components V, S
EFFECT
Range touch
Target living creatures touched
Duration 1 round/level
Saving Throw none; Spell Resistance yes
A black energy forms around the casters hand which is comprised of negative energy. Without harming the caster, this energy can be used to target, and harm living creatures touched. As a standard action Touch attack the energy deals 3d6+Caster Level in Negative Energy Damage to the target. If utilized as a part of a standard attack routine, attacks are rolled against the AC of the target as normal attacks, but multiple strikes per round become possible. This energy will heal Undead creatures instead of harming them.
Pack curses, these are your mid-level bread and butter as this type of character. Grab Reach Spell to give you distance, don't forget to utilize Spectral Hand. The Trait Magical Lineage will let you pick 1 spell which you can cast with -1 Spell Level when applying magic to it, allowing you to turn a Touch spell into a Close Ranged spell for free daily. Use this on what you feel will be your go to damage or disable spell each day.
You will want to pack Weapon Finesse, Dexterity as your 2nd best ability score after Intelligence. Weapon Focus: Touch Spell, Spell Focus and G. Spell Focus: Necromancy as your core feats. Allowing you to make Dexterity based Touch attacks and force higher DC's for your disables. As soon as you are able to, keep increasing your Intelligence score via Magic. This route bans out charms and abjuration for you, but you can still utilize evocation, transmutation, illusions to protect yourself, conjuration for your all purpose needs. Allowing you to be a buffer, nuker, summoner, or polymorphing yourself as needed.
Apologies for being so late, didn't see this until just now, and for the rambling disjointed response. Too early and lacked caffeine while responding.
