These are abilities any unit with a Stamina or Magic pool can perform, and do not take up slots on their “Ability” list. A character starts with these at level 1, or whenever they gain a Stamina or Magic Pool (whichever is required to be used).
Unless noted that an effect is permanent or has a specific round duration, it is to be assumed the effects of the ability/spell last until the end of the battle. In addition to this, unless specifically stated it is assumed maneuvers and spells that grant increases do not stack unless they specifically say so.