Sounds good to me!
Standard Multiweapon Fighting as a bonus feat?
Fading next?
So shall we try repurposing the ethereal jaunt ability of the Phase Spider and Ethereal Filcher/Marauder or work something up from scratch?
NA +2 sounds good.
Yes, let's go with standard 30 ft speed.
OK on the superior MWF.
Hmmmph. Sure, let's drop darkvision. I guess we should mention that in the flavor text somewhere.
All-Around Vision seems appropriate.
I like that draft for Fading! That works great!
Just spitballing: their arm arrangement "doesn't accommodate archery," so should we give them a racial penalty to attacks with bows?
Any other special abilities?
Your proposed SMWF ability looks good, though I think "wield dual-wield shields" has an extra "wield" in it.
Archery Disability also works for me.
The gorging and fasting sounds like a lot of animals, honestly. I think I'd leave it as flavor.
If we're just going to max out 2 skills, I'd just go with Listen and Spot for warrior types like these. We could also peel off a few points for Climb and Jump, if you like. Something like Climb 2, Jump 2, Listen 3, Spot 3 in terms of ranks.
Power Attack is a bit boring but would probably make sense for the feat.
Let's go with your proposed skill distribution and Power Attack.
Let's see, these still need weapons and armor. The original text says "However, they favor suits of garishly-decorated plate mail with flaring shoulder-plates and long chain skirts." That text plus a direct translation of the AC bonus suggests maybe a breastplate, though I wouldn't mind full plate for them.
As for weapons, I think the ranged one should be a javelin. For the normal monster stat block, I'm thinking one two-handed and two one-handed weapons. Something like a greataxe and two longswords maybe. Any thoughts?

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.