The PH2 sentence you quote does not contradict or clarify the PH1 sentence I quoted. Either way, conjurations can create a creature.
The question is: Does the conjuration effect need to contain the word "creature" for it to be a creature?
It specifies that "conjuration" is it's own category (other than 'object' and 'creature'). A conjuration needs to be a creature in order to be a creature, by default a conjuration is just a conjuration:
"A conjuration you create uses these rules, unless a power description says otherwise.", explaining that usually a conjuration cannot be attacked, moved, don't occupy, etc, and includes general rules for if they can be attacked, moved, etc.
A conjuration is it's own category of entity, and it doesn't interact with the world in any way except in the ways under the Conjuration rules, and that of the power.
For example, Storm Pillar:
Effect: You conjure a pillar of crackling energy in an unoccupied square within range. The pillar occupies 1 square
It cannot be targeted, doesn't provide cover, but explicitly occupies a square so it can't be walked through.
Caustic Rampart:
Effect: You conjure a wall that consists of contiguous squares filled with acid. It can be up to 5 squares long and up to 2 squares high. The wall lasts until the end of your next turn. Any creature that starts its turn in or adjacent to the wall takes 1d6 + Intelligence modifier acid damage. The wall is difficult terrain, and the wall’s squares are lightly obscured.
Caustic Rampart is in 5 squares, but doesn't occupy the squares, it just gives those squares epcial rules.
Onyx dog:
Description: When you activate a figurine, the conjured creature appears in a space adjacent to you,
Note it says "conjured creature" and not "conjuration". An Onyx Dog is NOT a conjuration, despite it being created by a conjuration power.
And look at Spellplague Guardians:
Effect: You conjure five human-shaped creatures. Each occupies 1 square. When you take a move action, you can move each conjuration 3 squares. Enemies can’t enter a square occupied by a conjured guardian, but allies can move through the guardians’ spaces as if the guardians were allies. The conjured guardians grant cover to allies but not enemies.
Note that
a)
it specifies that allies can move through them "as if they were allies"- not that they are allies
b) it specifies that the guardians grant cover.