Even though they don't work with Kess, there's merit to having
Animate Dead,
Necromancy, and
Dance of the Dead for the possibility of a quick reanimation. You have plenty of other things to flashback and you're stocking the yard selectively through looting and similar effects, so there's not much danger of losing the option.
Songs of the Damned seems significantly worse than
Dark Ritual if you're after that effect. You don't really want to be overloading your yard with reanimation targets. You can already drop them just before reanimating pretty effectively, so there's not much use to exposing them to GY hate if you don't have to. You're also not milling yourself to fill the yard, so it's less likely you're going to have a bunch of creatures there early. Rituals drop off in power pretty rapidly (even with Kess flashback) as you have more permanent mana sources, so you probably want to go for the early game option.
Secrets of the Dead is very on theme but has never played well for me. You're mostly using Kess for flashback, which is 1 card per turn. That's about the same as
Phyrexian Arena with a marginal upside of being able to flash something back the turn it comes in and the downside of relying on your general to function at all. I'd consider swapping that for a straight card draw spell. Something like
Painful Truths feels a lot better, given that you have the manabase to reliably cast it for 3 colors and can still take advantage of it with Kess. I also like the smaller card draw like
Chart a Course or
Night's Whisper for similar reasons.
You're also a little low on permanent mana sources. You have a curve that goes up to 5, assuming that you're treating the majority of the 6-drops as reanimation targets. You also don't have a lot of cheap (CMC ≤ 2) draw and filtering to make up for that. I'd try and find space for another couple lands. If you want to keep the pure singleton aspect for
Tainted Pact, snow-covered basics are uniquely named, help you play around any potential nonbasic hate a little better, and are easy to find right now thanks to MH1. If you want to stay low to the ground, ditching some of the 5 CMC reanimation spells for more low CMC draw and filtering can keep you churning through your deck throughout the game while also helping you hit land drops in the first few turns.