I posted this in the rules forum but it looks like this may be the appropriate place. If that is the case my original post can be deleted (I can't seem to delete or edit it myself). Sorry about that.
Looking through the class options it seems there are two types of multiclass.
The standard multiclasses: Brigand, Friar, Illusionist, Mage, Monk, Outlaw, Wizard, Warrior Mage, Warlock and Ranger, whose requisites are those of each of their component classes (or somewhat lower than that in the case of the Friar.)
And "prestige" classes with specific background info and higher minimum requisites: Paladin, Paladinic Ranger, Storm Rider, and Trollhunter.
The Trollhunter is replicated by the Warrior Mage and the Paladinic Ranger by the Ranger for those who don't want to or can't meet the requisites but the Storm Rider and Paladin have no corresponding classes. So anyone who wants to play a Cleric/Spellchanter/Thief or a Fighter/Cleric can only do so if they meet the higher requisites. This isn't such a big deal for the Storm Rider as the requisites are only 1 point higher (5 dex instead of 4) but the Paladin requires 5/5/5 stats which is far higher than the 3/5/3 that a standard Fighter/Cleric or Cleric/Fighter would need.
Perhaps a "Warrior Monk" or "War Priest" standard fighter/cleric or cleric/fighter multiclass could be created?
Also, the Paladin description says "gains powers after 3rd level as per traditional Paladin." Does this mean that the class cannot use miracles until after 3rd level?