You could make it an houserule that goes with the prestige class, but it is just that; an houserule. Officially, they are still differently named but mechanically similar abilities.
Makes sense
True necromancer gets nothing of the sorts. They receive a bonus on caster level when casting necromancy spells (not just those related to undead).
Effective caster level is different from caster level. Permanent effects like Necromantic Prowess and Practiced Spellcaster increase the caster level, but the effective caster level is equal to the permanent caster level + temporary effects. Spells use effective caster level for most things, but the control limit on Animate Dead is a notable exception.
No Arcane Disciple bonus feat then? At least it wouldn't let them use a domain spell more times per day than an actual cleric (as many times per day as they have spell slots, versus 1 time per day per spell level).
Not the epic feat, the necromancy specialist variant. Making it the same as Corpsecrafter is an houserule, it is not an official rule, as Realms of Chaos noted earlier in the thread. By RAW, most of the things I listed stack (a slightly less broken interpretation is that the necromancy specialist variant only applies to spells cast as a wizard, and the dread necromancer class feature only applies to spells cast as a dread necromancer, but all the other things definitely stack).
I was poking you on your sudden use of an abbreviation (you used it only there) in a place where the long name should have been used.
I was very clear on what I meant. Reword it "If an undead created by the Lord of the Undead would have (or currently has) a Charisma score lower than 1 + its Lord of the Undead class level, it is raised to this amount. When the Lord of the Undeath's class level increases, the threshold changes, and creatures with a Charisma score lower than the new threshold have their Charisma score raised to the new amount." You'll get zombies with 11 Charisma, but no spectre with 25 (or devourer with 27).
Then don't use the words summon or summoning at all. Rename it teleportation glyph and consistently say it teleports (does not summon) the undead to you. Summoning has a clearly defined meaning in the rules of D&D, and that meaning includes the notion that a summoned creature doesn't die if killed as a summoned creature, merely taking 24 hours to reform to its home plane.
Wrong and wrong. The dread necromancer ability gives a control limit of (4 + Charisma modifier) * class level. This ability gives a control limit of (4 + Charisma modifier) * 4. Unless your caster level actually is 4, the former is way, way better than the later. Furthermore, I'm beginning to assume you don't know enough about how to be a necromancer in D&D. Desecrate is neither a caster level hack, nor a shenanigan. The 64 HD skeleton I gave as an example? It only requires a caster level of 16.
Try this: "At seventh level, any mindless undead created by the lord of the undeath receive benefits equivalent to the Awaken Undead spell, except it grants an Intelligence score of (1d6+4) plus one-half the lord of the undeath's class level, and isn't limited by the Intelligence score that the undead creature had in life."
Seems to work.
As is often the case when paragon creature actually gets discussed, this is a thought experiment. I still think CR is not a good way to judge a monster's power level, so what about the following: base creature's HD plus template's LA must be equal to or lower than the lord of the undead's caster level.
Of the listed templates with an LA, you have: death knight (LA +5), ghost (LA +5), ghost brute (LA +5), gravetouched ghoul (LA +2), mummified creature (LA +4), and vampire (LA +8). Umbral creature should be LA +5, based on a similar template from Savage Species (assuming the base creature's class levels are retained; the Libris Mortis version is weird in that regard). Ignoring Swarm Shifter, the only templates on the list without an LA actually are bone creature, corpse creature, necromental and revived fossil. I'd go with LA +2 for the first two, to make them viable options against gravetouched ghoul, and maybe LA +1 for the other two.
Swarm Shifter has no LA, which I actually think is an overlook from WotC's part. I'd place it at about LA +3 at best, maybe LA +2, with a +1 increase for every 2 swarm forms beyond the first.
For deathlock, use the ghast as a balance point. For slaymate, use the mummy.