I think you're spot-on. And I had exactly this same issue, with exactly this same passage. It was the realization that this passage is, in fact, including baptism in its scope of faith, over against works
of the law, that shook me loose from the Evangelical understanding. This came through a comparison with the nearly parallel passage in Colossians. Years ago I wrote the following elsewhere...let me know if this thinking makes sense to you. I suspect it will, given what you've already posted. I'm genuinely curious what a Lutheran would make of this...wherever will I find one?
(Ps. at the time I wrote this, I was on my exodus out of Calvinism)
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Eph. 1 is kind of a locus classicus of Reformed teaching on election, right? "In love He predestined us..." and so forth. Eph. 2 is said to lay out total depravity, from which we are then rescued by grace through faith alone, "by grace you have been saved, and that not of yourselves, it is the gift of God..." Of course this is generally presented as an individualistic affair--each is elected and saved--and the church becomes the collection of saved individuals. But the more I read Paul's letters, the more I think he's coming from exactly the other direction, speaking coprorately first. And I don't think his use of "us" and "you" in Eph. is intended toward individuals, either, but rather Jews and Gentiles. Maybe I'm goofed up but let's try this out...
So here Paul is beginning to speak of "us" and "we" being blessed by God from before the creation of the world, etc. He made known to "us" the mystery of his will, which mystery is to bring all things (i.e. all creation) together under the lordship of Christ, and of course, preeminent in Paul's thinking about this mystery typically is the inclusion of Gentiles in the covenant. Then comes the great predestination passage...
Here he's saying that "we" were chosen. "We" who? Apparently, "we who were the first to hope in Christ." I'm thinking, seriously, that he's talking about the Jews and more specifically the Jewish Christians. Israel was first to hope in Christ, as "to them belong the promises" of the Messiah (cf. Romans). and it was from Israel that the Messiah came, and he was believed on first by Jews who had ears to hear and eyes to see (in the Gospels of course Gentiles had faith too, but even Jesus said he came first to the lost sheep of Israel.) So Paul could here be speaking of the Jews as being those predestined--as a group foreordained to receive the Messiah. Paul and the rest of the "we" seem a natural fit for the description "who were the first to hope in Christ." OK, and at this point Paul quite suddenly switches to the 2nd person:
"You also," I'm thinking, means "you gentiles also." So the common bond is Christ, the head of all things. All who believe in Him are marked and sealed with the Spirit (think of Peter in Acts saying "Now I see that God has given the Holy Spirit to the Gentiles also."). In v. 14 he says "our inheritance..." who's inheritance? That of the believing Jews, which has now also become the inheritance of the believing Gentiles. The promise is now open to EVERYONE. This jives perfectly with his thinking in Romans that it is faith that makes one a child of Abraham (and therefore an heir to the promise) and that the Gentiles were grafted into Israel--they didn't replace it or start anything new. Moving on now to the end of Ch. 1 and the beginning of Ch. 2...
He begins by describing the church, which has Christ for its head, and then moves on to say "YOU...were dead in sins." I think he means "you GENTILES were dead in sins" based on a slightly later paragraph--though he also says that "we all" were once that way, meaning both Jews and Gentiles--they were "saved" at different times, but in the same way. Abraham walked according to the course of this world, and even is described as an idolater in Hebrews, but he was chosen by God and believed in God's promise, and was set apart to receive the inheritance. That promise culminated in the coming of Christ (cf. Galatians and the part about "one seed" being Christ) and the Gentiles now, at this time in history, also have access to that promise by faith. And when Paul says "made us alive together with Christ," I've always read that as meaning "we and Christ together were made alive" but I wonder if it doesn't mean "we Jews and Gentiles, together, were made alive....with Christ." Seems to fit v. 6 also...
That faith is not of the Gentiles (not of yourselves), but rather it is the faith of Abraham, the faith of Israel, which has been given to the Gentiles as a gift of God. And of course we are not saved by works, whether of the Law (Jews) or otherwise (Gentiles) but by grace, so that together we can do good works pleasing to God. And now the rest of Ch. 2 which further confirms this line of thinking, to me...
Ah, the heart of the matter, no? Why were the Gentiles dead in sin? As you said earlier they were dead in so far as they served themselves and did evil works, seeking to please themselves and not the true and living God. But they also were "as good as dead" in their sin, so to speak, because death was all there was remaining for them. They were cut off from Israel, not bearing the mark of the covenant in the flesh, and were at enmity with Israel. So they were dead both figuratively and literally. But now "you who were once far off" have been brought near...to what? To the promise, and now to the resurrection, the end of death. No longer dead in sin, and no longer at enmity. This whole passage says that God, through Christ, has made peace between Jew and Gentile--no longer is circumcision the mark of inclusion with God's covenant, but it is faith that unites. And then Ch. 3 begins to describe how the mystery now revealed, first to the Jews and now to all, is that God is to include Gentiles in this covenant. So from start to finish, Eph. 1-3 seems to be primarily about Jews and Gentiles, not individuals. Individuals surely are included but Paul's thinking is first and foremost corporate.
Now let's look at Colossians, (where Ch. 1 began by establishing Christ as creator, sustainer and Lord over all creation):
Same theme, right? Gentiles were at enmity with Jews in the flesh, but have now been reconciled so that together all will belong to and glorify Christ. And if the individual idea of predestination isn't presupposed as with Calvinism, the warning to continue in the faith in v. 23 makes more sense. Now, keeping in mind Eph. 2:11-12, let's look at Colossians 2:
An exact parallel to Ephesians! Gentiles, lacking the circumcision made with hands in the flesh, now have received that made without hands, the true circumcision that unites ALL to Christ, which circumcision is BAPTISM. This is the key verse in the Presbyterian defense of infant baptism, right? They get the connection, but miss v. 13!!! Which says, like Ephesians, that they (Gentiles) were DEAD IN TRESPASSES and the UNCIRCUMCISION of their flesh. Their deadness consisted in sinful behavior AND exclusion from the covenant. God has now made them alive and forgiven their sins through baptism. He wiped out the handwriting against "us" (the Jews, the Law) and now all have the same access to the Father, through faith (Eph) and Baptism (Col.). Looking at this incredible parallel, i hve to conclude than in Eph. 2, when Paul says "you" were dead in sins, he absolutely primarily means "you Gentiles" and that when he speaks of them having been made alive and saved by grace, he is referring to their baptism. Which is inseparable from faith of course (Col. 1:23), but I cannot see how he's treating baptism as a "sign and seal of what is received by faith" and not as that which has actually effected union with Christ. Paul then moves on in Col. to instruct them to no longer be subject to either ritual Law (sabbaths, unclean foods, etc.) or to lusts of the flesh, but rather to serve Christ in faith.
Taken together, this view of Ephesians 2 seems consistent with Paul's other letters, with the Gospels, and with early Christian thought. It does not, then, establish total depravity. And baptism is synonymous with "being saved by grace through faith."