Level 89 Raise Zombie Necromancer^3.26

Notes

I've prepared a written guide because I'm too lazy for a video guide. This is the concept I'm using to level up since 3.24 and I find it superior to all minion leveling guides I've tested so far.

Campaign notes:

Mule shadow and get 2x chance to poison. Then marauder for 2x ruthless. Pick 2 items that have BBG or BBR. Pick zombies and level it offhand. Pick Freezing Pulse as reward for entering Lioneye's Watch. 
Switch your BBR wand to another BBG whenever possible. If you happen to have R for 3 link use ruthless. At level 4 get srs. After Hailrake buy 2x summon phantasm. 
Rush for closest minion defence wheel (better top of Guardian starting area) and pick "Minions gain 5% life on minion death" mastery (when minions despawn it also counts as if dead). 
Then go Enduring bond wheel. Your main links now are Zombie+Phantasm+Chance to poison and SRS+Phantasm+Chance to poison. Replace srs with skeletons (Brutus reward). BBG is your main 3-link for all damaging minions.
 Buy Flesh offering and level it to 8. Aim for 4 link for both of your minion skills. Buy and level 2x withering touch from Siosa. Your main 4 link is BBGG with added withering touch
If you happen to get BBBG plug in minion speed or minion damage or added chaos damage. If BBGR - ruthless again. No heralds. Pick minion speed as a reward for killing act2 spider.
Other (some after Siosa): Blasphemy - Despair, CWDT(1) - Flesh offering(8), Automation -> Steelskin, Determination, Vitality or Clarity possible atm, after mana reservation wheel replace with Flesh And Stone (Sand).
No changes after act 4 except better links and/or colors. Ascendancy: Mindless Agression -> Bone Barrier / Unholy Might -> Unholy Might / Bone Barrier. No AG. All spectres frenzy monkeys.
BBBG Spectre+Minion LIfe+Feeding Frenzy + Culling Strike

This completes the campaign

Further tests:
It's actually better for either zombz or skeles (not both) to have melee splash and added chaos / minion speed instead of withering touch and phantasm. Not that much dps loss on bosses, much better clearing.
You will have excessive mana without good options to reserve it early - consider picking arctic armour as chamber of sins reward and use for some time.
Best anoint for campaign: Cloth and chain (12% ele res, 24% evasion/armour) (Clear, Clear, Azure). Can be obtained early as act 3 sewers have guaranteed Blight spawn

Mapping notes:
Skeletons will start dying at red maps no matter what - consider replacing with chaos golem of hordes (at any time when the price is good maybe even at campaign) but remember to respec minion life on minion death mastery.
Purity of elements is ok up to t10 maps - after 4th ascendancy get commander of darkness and switch to determination
have desecrate active somewhere - this is a nice option to order your minions to go to the specific location (like if for some reason 5 zombies are attacking but 3 zombz + 1 spectre are somehow idle then just press desecrate somewhere near the boss while staying offscreen)

Essential mapping items:
- Skullhead (2c at most at 1st week). Alongside with Decay ward passive this solves minion survivability in t16 maps.
- Victario's influence (1-2c for 1st week, tends to be cheap no matter what). We need auras for minions.
- Careful planning (5-10c) (or use vaal orb on viridian jewel, some say chance is 1/10) OR rare item with dexterity and the need to allocate +30 dex
- 5Link warstaff (attack block implicit). You will craft it using essence of fear for minion damage, then benchcraft minion attack and cast speed. You'll also take staff block nodes. 
That kinda solves your survivability in red maps (remember you're not supposed to facetank everything, let your minions engage the enemy)
* Staff block may reach 70/70 non-glancing block only with passive tree points nearby and allows 6-linking minions. Together with improved auras from Vict this is quite nice.
Shields tend to reach 75/75 block only with bone offering and Mistress of Sacrifice. 
If we want that we'd need 6-linked chest, we'd have weaker auras and more mana reservation that may completely shut down one of our viable aura and remove Cmdr darkness. 

Useful:
Rainbowstride (2-3c, spell block, resistance, movespeed) - nice and cheap but lacks hp
Perquil's toe (1c) - damage upgrade and dexterity stub but lacks hp and reduces tanking
Voideye (2-3c) - ring for AG in case u're ok paying extra c for the items
Belt of the deceiver - have some resistances, not that much hp, but cheap
*Hungry loop for AG is not necessary because of minion blocks
*I've managed to grab 2 voidstones while having some items from the campaign that only had good amount of hp and benchcrafted double resistances. These uniques aren't that necessary.

White tier maps:
essential mapping items are well enough for white tier maps. Need one rare item with dex.
You will likely have 4-6 c as natural drop while doing campaign which is enough for initial buying. Consider doing 1st lab for random transfigured ge

Yellow tier maps:
replace skele with carrion golem of hordes
some staff block nodes

Red tier maps:
complete Uber lab - get Commander of Darkness
get 6l staff: zombz, cg hordes, chance to poison, multistr, msplash, min speed. Replacing melee splash for ruthless / melee physical is an option on bosses (I didn't)
get full staff block nodes till 70/70
get 2x minion taunt jewels (so that red map bosses rarely switch aggro to you). Can alt spam any ghastly eye jewel ilvl 65+ for max tier taunt mod.
you will likely need careful planning jewel for dex at this point (or buy another dex item)
upgrade flasks - get granite + jade for phys mitigation. Automate it. Overflowing chalice (flask that helps other flasks getting charges) is nice 

Eater:
kinda hard to fail the inescapable doom phase assuming you have enough movespeed and steelskin automated

Exarch: 
if you have bone rings with minion movement speed, haste on victario and minion speed linked then it is possible to explode spheres by ordering your minions to go there via desecrate. return your minions using convocation or desecrate on yourself.