I don't see the issue with kemmler as general with ld9, in troop reference summary and bestiary he has ld 8,
but in the army list and gw's url he has 9.
where he has ld 9 is where you pay 350 pts for him, so that's what I'd use.
your general has to be a wizard, and he must have the lore of the vampires. of these wizards the one with the highest ld must be the general.
in my book, taking a vamp lord with death, or shadow disqualifies him as general, so the master necro with vampire lore is general. unfortunately noone else reads it like this, but instead forces the vamp lord to take vamp lore, cuz he has highest ld....