"Laying On of Hands" in Heb 6.2
The first move in the argument is, as usual, the most important: The "elementary teaching about the Christ" in Heb 6.1-2 refers to Old Testament teachings about Israel's messiah. That rules out a reference to chrismation. Further, the list of teachings in vv. 1-2 is for baby Christians, which would seem reasonably to rule out a reference to ordination.
Rather, the elementary teaching of the OT that even a baby Christian needs to understand is teaching on the substitutionary atonement -- that Jesus died for our sins. Further, the stuff about "laying on of hands" in Israel's sacrificial system is absolutely critical to understanding God's plan of salvation in the Old Testament as well as the New.
So let's consider the evidence. First, while it's often overlooked, it seems pretty obvious to me that the list of elementary doctrines in Heb 6.1-2 is a list of elementary doctrines taught in the Old Testament. Consider:
 The discussion of Melchizedek begun in Heb 5.1-10, is interrupted by the author's rebuke in vv.11-12 about the need again to be taught "the elementary principles of the oracles (Gk) of God." The word "oracles" seems to be a term of art that NT authors used to refer to the "OT scriptures," see Acts 7.38 (Gk), Ro 3.2 (Gk).
 Consider the motivation for the rebuke in the first place: The author is discussing the OT priest Melchizedek. The writer then interrupts his discussion, pointing out in vv. 11-12 that "concerning him we have much to say, and it is hard to explain, since you have become dull of hearing. For though by the time you ought to be teachers, you have need again for some one to teach you the elementary principles of the oracles of God . . ."
So the whole point of the rebuke is that the writer's readers (or listeners) don't understand the elementary teachings of the Old Testament. The argument about Melchizedek is then picked up again starting in 6.20. So 5.11-6.19 seems to be a parenthetical argument, motivating the importance for understanding the OT ministry of Melchizedek in light of Jesus' ministry.
 The reference to the "elementary teachings about the Christ" in 6.1 then parallels the reference to "elementary principles" in 5.12, which is almost certainly a rebuke about not knowing the OT. (The "therefore" in 6.1 indicates a continuation of the argument that the author began in chapter 5.)
 Heb 6.1 refers not to "Christ" but to "the Christ." I.e., to elementary teachings about the Messiah. (The NIV drops the article.) The OT anticipates the messiah, but does not anticipate Jesus by name. So the use of the article seems suggestive here.
 So, too, the instruction about "baptisms" (plural) in 6.2. The plural is easy to understand if it has reference to the several different OT baptisms, but would sit oddly if it refers to the "one baptism" of the NT.
 Overall, the "laying on of hands" in regards to substitutionary atonement seems more to be an "elementary teaching" that baby Christians (5.14) need to know relative to ministerial ordination.
So here's the way I would understand Heb 6.2 in the overall trajectory of the author's argument starting in Heb 5.1:
Learn about the high priest by looking at Melchizedek (5.1-10). But you don't know enough even about the basics of the OT to learn from the example of Melchizedek (5.11-14). We need to press on to maturity (i.e., learning about high priests from the example of Melchizedek), not again learning the OT baby lessons -- repentance, faith, baptisms, substitutionary atonement, resurrection, and judgment (Heb 6.1-3). These are foundation lessons that cannot be rejected (6.4-12), but do not fear, because God is faithful to his promises in redeeming us (6.13-20). So now let's return to what we have to learn about Melchizedek (Heb 6.20ff).
Note also that understanding the "laying on of hands" reference in 6.2 as a reference to the OT sacrificial practice fits with the overall theme of the book of Hebrews, i.e., teaching how the OT points to, and is completed in, Christ.
So what's the upshot?
First we should be chastened by the author's rebuke about ignorance of the Old Testament, "for though by this time you ought to be teachers, you have need again for someone to teach you the elementary principles" of the Old Testament. Christians are called to understand the Bible, the whole Bible. I cringe at my ignorance of the OT every time I read the author's rebuke in Hebrews 5.
Secondly, that a representative will die for our sins is part of the woof and weave of God's redemption in and through the messiah. The transfer of our sin to a representative is one of the "elementary teachings about the messiah" in the Old Testament, as it points to and anticipates Jesus. We receive a fuller understanding of Jesus' ministry and vocation by understanding what the Old Testament teaches us about him and his work.
Finally, consider the "solid food . . . for the mature" (5.14) that the author then discusses throughout the rest of the book. Matters of parallel priesthoods, OT temple architecture, OT geography, and OT sacrifices. These are "mature" teachings, but as the remainder of the book of Hebrews testifies, these "mature" teachings are also radically Christocentric. Jesus and his work is the heart of the Scriptures from beginning to end. As the Scriptures unfold to us, they more deeply reveal only Christ and his work.