Good ideas. +2 Str, -2 Cha from hypnos?
Good idea, but I'd make the swap a bit more than that. It's a rather plebeian golem without any Su attacks, so does it need a Charisma bonus?
+4 Str and -4 Cha from Hypnos.
"Warrior" BAB. (I wouldn't give it a fighter's bonus feats, I think these are more like rank-and-file guards than the martial elite)
3 Hit Dice and NA +3.
Applied to the Hypnos that makes something like:
Magen, Demos
Medium Construct
Hit Dice: 3d10+20 (36 hp)
Initiative: +0
Speed: 30 ft. (6 squares)
Armor Class: 15 (+2 Dex, +3 natural), touch 12, flat-footed 13
Base Attack/Grapple: +3/+5
Attack: weapon +5 melee (?) or weapon +5 ranged (?)
Full Attack: weapon +5 melee (?) or weapon +5 ranged (?)
Space/Reach: 5 ft./5 ft.
Special Attacks: Warrior construct
Special Qualities: Construct traits, damage reduction 10/bludgeoning, darkvision 60 ft., low-light vision, spell resistance 7
Saves: Fort +1, Ref +3, Will +1
Abilities: Str 14, Dex 15, Con —, Int 9, Wis 11, Cha 10
Skills: 6
Feats: 2
Environment: Any
Organization: Solitary, brew (2-8), or concoction (2-12 magen of different types)
Challenge Rating: 2
Treasure: ?
Alignment: Always neutral
Advancement: 4-6 HD (Medium)
Warrior Construct (Ex): a demos magen has a full BAB.