[Bonfire]

Disclaimer: I've only ever played around with them in single player so take what I say with a grain of salt.
First the bless earth, nature, water and astral are what you want to look at. A minor fire bless would be a nice addition but you don't really have a good chassis for it unless you're going for a rainbow bless.

Earth(4-9): Keeps your sacreds from fatiguing out. Good for heavily armored sacreds, thugs, mages.
Nature(4-8): Keeps sacreds alive, affliction free. Good for all sacreds but especially for your thugs. N9 is a huge liability with sacred mages don't go that high unless you really know what you're doing.
Water(9): Helps to kill things faster and get hit less often. Great for your less durable lightly armored sacreds.
Astral(4-9): Keeps your demons from being banished. Twist fate can be surprisingly useful.

Which bless you take is going to effect which sacreds you recruit and summon. The biggest factor in my mind is whether you take an astral bless. Without it most of your demon troops are fairly easy to banish and you'll need to rely much more on your non-demon Kala-Mukha Warriors and high MR thugs.

With that in mind there are a couple pretender chassis that stand out to me.

Great Mother: E9N6 or similar
Lady of Fortune: W9S6 or similar
Mother of Rivers: W9E(4-6) or W9N(4-6) or W9E4N4
Oracle: S9W9 or S9E9
Crone: F4W4E4S6N6 or similar rainbow

As for scales:
Turmoil/Luck can work with a blood nation but you have to switch to a blood based economy very quickly to compensate for the lost income. Unless you're very confident going into blood go Order 3 with maybe misfortune 0-2. Order/Luck is nice but it's hard to afford with a decent bless.
Sloth-1 is easily tolerable but lower than that and you may have trouble recruiting a full set of you armored sacreds from your forts. Sloth-3 is workable as long as you plan to rely on your less armored sacreds at first.
Heat-3
Death can be a good place to pick up points.
Magic/Drain: Drain is very tempting to keep your demons from being banished but you're losing something like a third of your research potential on your non capital mages compared to magic 1. If you take drain just make sure you get something good enough to make up for that.