Multiclassing is not as likely in the Maalum setting due to the high cost of reinscription for multiclassed characters.
The general availability of retraining makes multiclassing somewhat different from other campaigns. This page attempts to clarify and resolve open questions or ambiguities.
First Level hit points
As long as the character's class levels would remain in a legal ordering, you may consider them reordered for the purposes of determining your first class level.
This does not affect the actual ordering of class levels on your character sheet, but does allow you to pick your character's first-level hit points from the class that gives them the highest amount of hit points—as long as there exists a legal ordering that places this class at first level.