Yep, the Template probably should have said that it only works on living corporeal creatures. When you change Type, all manner of weirdness happens. Imagine what it does to Constructs? Technically, they'd gain the Living subtype (which was not even invented until after this template was made as the Epic book came out in 2001 and Eberron Campaign Setting came out 2004).
As I said earlier, I don't make the rules but I do follow them as written. The template says to add +10 Con. The logic of that escapes me as well, but hey, I didn't make the template. I even checked the FAQ to see if there was a clue about this and it had nothing.
I actually prefer the Pseudonatural Creature template from Complete Arcane because the Con ability doesn't change and it specifically says it retains all the base creature's special qualities. If you use that template this is what you get:
Medium Outsider (Augmented Undead)
Hit Dice: 2d12 (13 hp)
Speed: 30 ft. (6 squares)
Armor Class: 14 (+2 Dex, +2 natural), touch 12, flat-footed 12
Base Attack/Grapple: +1/+2
Attack: Bite +2 melee (1d6+1 plus paralysis)
Full Attack: Bite +2 melee (1d6+1 plus paralysis) and 2 claws +0 melee (1d3 plus paralysis)
Space/Reach: 5 ft./5 ft.
Special Attacks: Ghoul fever, paralysis, true strike
Special Qualities: Alternate form, darkvision 60 ft., resistance to acid and electricity 5, spell resistance 12, outsider traits1 +2 turn resistance
Saves: Fort +0, Ref +2, Will +5
Abilities: Str 13, Dex 15, Con Ø, Int 13, Wis 14, Cha 12
Skills: Balance +6, Climb +5, Hide +6, Jump +5, Move Silently +6, Spot +7
Environment: Any land and underground
Organization: Solitary, gang (2-4), or pack (7-12)
Challenge Rating: 1
Alignment: Always chaotic evil
Advancement: 3 HD (Medium)
Level Adjustment: —
Ghouls speak the languages they spoke in life (usually Common).
Ghouls try to attack with surprise whenever possible. They strike from behind tombstones and burst from shallow graves.
Alternate Form (Su): As a standard action, a pseudonatural creature can take the form of a grotesque, tentacled mass (or another appropriately gruesome form, as determined by the DM). Despite the alien appearance, its abilities remain unchanged. Other creatures receive a -1 morale penalty on their attack rolls against a pseudonatural creature when it is in this alternate form.
Ghoul Fever (Su): Disease—bite, Fortitude DC 12, incubation period 1 day, damage 1d3 Con and 1d3 Dex. The save DC is Charisma-based.
An afflicted humanoid who dies of ghoul fever rises as a ghoul at the next midnight. A humanoid who becomes a ghoul in this way retains none of the abilities it possessed in life. It is not under the control of any other ghouls, but it hungers for the flesh of the living and behaves like a normal ghoul in all respects. A humanoid of 4 Hit Dice or more rises as a ghast, not a ghoul.
Paralysis (Ex): Those hit by a ghoul’s bite or claw attack must succeed on a DC 12 Fortitude save or be paralyzed for 1d4+1 rounds. Elves have immunity to this paralysis. The save DC is Charisma-based.
True Strike (Su): Once per day, a pseudonatural creature can gain a +20 insight bonus on a single attack roll. In addition, the creature suffers no miss chance against a target that has concealment or total concealment when making this attack.
1 even though this ghoul is an outsider, it is still has no constitution score.
A creature with no Constitution has no body or no metabolism. It is immune to any effect that requires a Fortitude save unless the effect works on objects or is harmless. The creature is also immune to ability damage, ability drain, and energy drain, and automatically fails Constitution checks. A creature with no Constitution cannot tire and thus can run indefinitely without tiring (unless the creature’s description says it cannot run).