The phrase "all the key elements" is correct and usable in written English.
You can use it when referring to the essential components or aspects of a particular subject or situation.
Example: "In order to create a successful marketing strategy, we need to consider all the key elements, including target audience, budget, and messaging."
Alternatives: "all the essential components" or "all the crucial factors".
In fact it was well measured and included all the key elements.
In my article, "Trial by Fire," I examine in depth all the key elements of the prosecution's case that led to Willingham's indictment and conviction.
The plan now is for world leaders to come to Copenhagen next month to sign a politically binding agreement which would have all the key elements of the final deal in it.
After months of high-level diplomatic haggling, the B.S.A. text contains all the key elements that the U.S. demanded: immunity from Afghan law, rights to military bases, and permission to continue counterterrorism operations.
In the sketch of The German Ideology, all the key elements of historical materialism are present, even if the terminology is not yet that of Marx's more mature writings.
The 10-minute seder will incorporate all the key elements of the traditional seder, in English and Hebrew, but condensed to make sure it can fit between sets.
By the turn of the 15th century, all of the key elements that came to define humanism were in place except for two: its detailed educational system and what might be called its Greek dimension.
The paper presents the design of the simulator with all of the key elements described.
All of the key elements are in place to remove Syria's most dangerous chemical stockpiles, but the process of getting them out of the country may be delayed beyond the original 31 December deadline.
The Enterprise Architecture refers to a comprehensive description of all of the key elements and relationships that make up an organization [Harmon, P. (2003). Developing an Enterprise Architecture, Business process trends: Whitepaper].
The manga interprets the series with all of the key elements intact, and tells the events of the anime with a crude artwork and unsteady pacing.
