Steven B.,
That's some set of questions! First, the LCMS is nowhere near homogenous in whom it communes. The parish I attended as a teen invited all baptized Christians who confessed the real presence of Christ's body and blood for forgiveness of sins to attend; though not explicitly stated, that was also the approach at Concordia Bronxville when I attended there. It was not until I came to the seminary that I really encountered churches that taught and practiced that only confirmed members of the LCMS or of a sister church with whom we were in altar and pulpit fellowship would be communed, but even then, these parishes have always allowed for pastoral discretion in dealing with exceptional cases.
Is an ELCA pastor or layperson who protests against the ELCA's communion fellowship practices, and yet remains within her, an exceptional case? I don't think many Missouri pastors would be comfortable simply saying: "Yes" or "No" to that. Most, I suspect, would be comfortable dealing pastorally with the situations that arise on a one to one basis. And Missouri pastors are all to well aware - as your example pointed out, and as my history witnesses - that there has been for some time a wide divergence in actual practice inside of Missouri and yet we've not reached the point of not communing each other.