You're being pretty cryptic--i.e. it's not simple to discern the focus of your request.
Are these chapters "connected?" In some sense, yes. In the first two, you have ceremonies for formal enactment of covenant; though you can also argue that the covenant essence of promise-obligation precedes the ceremonial activity. In Heb.9, you have explicit reference to the second (Sinai) ceremony, so clearly the author is directing his readers to recall the former episode.
The Gen.15 passage is unique, in that God makes it clear that he is making a unilateral promise. Whereas, in some bilateral pact, a lord and his vassal, or two more-or-less equal parties would walk through spilt blood and carcasses together, binding them on both sides to an agreement that one was worthy of death should either of them break faith. Yet, here God passes alone through the pieces and the blood to emphasize that (as Heb.6:17-18) God's oath is added to his promise for our assurance: He will (all by himself) guarantee salvation; though it be through death, he will do it.
In Ex.24:3, it is plain the children of Israel promise obedience, as loyal subjects to their King and Rescuer. Yet, we cannot describe Sinai purely in terms of a bilateral agreement. There is some "mixing" of categories. Beneath everything is the bedrock of God's unconditional promise to Abraham, a covenant that the later covenant cannot supersede or override, Gal.3:17. On the surface, there is quid pro quo, protection and deliverance in the future predicated on unswerving obedience.
At the level of corporate identity, Israel-as-a-unit agrees (in principle) to do as Adam, and obey God as condition of remaining in God's favor and in the Land (Garden). Fundamentally, this is an impossible commitment, both individually and corporately; which is why there is a whole sacrificial system at the heart of the Old Covenant, the design of which is to teach the Covenant of Grace. Israel cannot keep covenant for even 40days (Ex.32), cannot even get the ritual in operation before they have corrupted themselves. "You cannot serve the Lord," Jos.24:19.
Yet, the persistent proofs are never sufficient evidence to convince the people (though sometimes more, sometimes less of the individual members) that they are inveterate sinners, and can never earn their reward. If they could have been convinced, it would have been because they had all been given that "new heart" which was able to see the utter grace of their deliverance from death, and that grace was sustaining them all the way to their eternal home. And that it was grace (alone) that made thankfulness and heartfelt obedience.
Treating the Sinai-covenant like a strict covenant of works was never going to succeed. It was impossible, obviously impossible, and the very form of the religion embedded in the covenant taught them this. Unless, they perverted the lesson into a works-righteousness system; which is precisely what they proceeded to do, at least by the time of Christ.
Arguably, the failure of the people of Judah at the time of the Exile was something of the opposite extreme--a presumption on "grace," a reliance on the "form" of religion to suffice for the lack of heart-devotion to the meaning of the faith. The people believed Jehovah would never let his Temple be destroyed, so long as the sacrifices were faithfully carried out. But this view was ritualism, not true grace. The nation was trying to "purchase" divine protection, while intent on maintaining their evil habits.
So, were the blessings and curses of the Sinai covenant simply another "ritual" pointing to something else? Were they "real," given the people's acknowledged weakness? They certainly were real, because the negative sanctions were historically carried out against the nation, eventually. They were typological, pointing back to the original Fall-failure, and ahead to Final-judgment. If corporate-Israel had been obedient, real lasting blessing would have been theirs.
As it was, their half-hearted obedience over many centuries was treated by God in a very lenient fashion--another lesson in grace that was there for the taking, but which was also generally missed or perverted. But at long last, it was time to demonstrate further (again, the typology) that God will not forever endure rebels, most especially the presumptuous kind; and the secret animus of them that hate him while pretending love. If you treat the Sinai covenant like a covenant of works and conditional all the way down, don't be surprised when God honors it as such.
Heb.9 uses the symbols of the sacrificial system instituted at Sinai (which has background going all the way back to the Fall) to unpack the work of Christ, who is the fulfillment of all the symbolism of the Tabernacle/Temple, and indeed all of the ceremonies of Israelite religious life (as given in the Law, not as frequently practiced and borrowed from idol-devotions). Christ's sacrifice accomplished what the brazen-altar-sacrifices promised and anticipated. His work is: God going even unto death if need be (and was required), to keep his covenant oath to give his people eternal life.
No one--not Abraham, not Noah, not Moses or Aaron, not David, not Peter or John--no one from Adam on down has kept the covenant of Works; except for Jesus. In that, we all of us ordinary children are covenant breakers. For believers and only them, the Lord has taken in himself the penalty due us.
