Two things spring to mind from these sentences. Firstly, that these lands had never been permanently occupied by the British and the Wabanaki use this legal concept to justify their sovereingty. (i.e. de facto control and domestic sovereignty).
Secondly, a major difference is expressed by the Wabanaki in this text. They explicity deny swearing fealty to the King of France (Louis XV) which might very well be true even if they had sworn an oath of fealty to Louis XIV prior to 1715.
From my understanding, under French monarchical law subjects required a renewal of their oath of fealty upon the succession of each monarch. The office of the monarch was not considered a legal person in the way which this office is/was considered under British law at the time. The oath was not to the office of the French monarch but the monarch themselves.
Hence, the Wabanaki argue that they are not bound to the French monarchy even if they had sworn fealty to Louis XIV in the past. So the present King cannot justify the land transfer as he is not sovereign over the Wabanaki.