The effect of “Level Limit - Area B” does not use the chain, it is a continuous effect.
All Level 4 or higher monsters face-up on the field after “Level Limit - Area B” resolves will be in Defense Position. You can change the Battle Position of a Level 4 or higher monster, but it will immediately be changed back to Defense Position because of “Level Limit - Area B”’s effect.
If “Level Limit - Area B” is activated while “Final Attack Orders” is active, then the most recently resolved effect takes precedence and monsters Level 4 or higher will be in Defense Position.
If you Summon “Spell Canceller” while “Level Limit - Area B” is on the field, “Spell Canceller” negates its effect and is not changed to Defense Position.