Paul's Head Coverings (1 Cor 11) and Baptism of the Dead

I'll be coming up with a post about the Ancient Christian practice of head veiling soon. Paul, according to Mormons, commanded baptism for the dead 1 Corinthians. While his one-verse acknowledgement of the practice is taken as proof that it was taught by the Apostles, meaning the LDS church can maintain its stance as a Restoration of the church before its apostasy, an entire commandment by Paul is ignored about women wearing a head veiling during prayer. What happened to restoring the ancient practices of pre-apostasized Christianity?

Paul said of the commandment: "But if one is inclined to be contentious, we have no other practice, nor have the churches of God." (1 Cor 11:16, NASB)

For what, today, seems to be a commandment rejected as born from a culture that's no longer around, we're left begging the question: if a commandment that was this serious in Paul's writings can be thrown out for pertaining only to a culture from long ago, or that Paul was mistaken due to cultural norms that no one follows anymore, what else in his writings were born from cultural norms alone? Should we toss out other commandments that were born from the mistaken assumptions of a culture?

If head veiling was a widely and officially accepted practice among the Ancient Christian church, but baptism of the dead--which deals with salvation of the dead and not just culturally-driven modesty--didn't make it, then what does that say of the claim that the Apostles actually taught baptism of the dead to the ancient christian church?

More on this later, when time allows. First, a repository for useful information:

FAIR on Restoration:
Thus, the Latter-day Saints claim their church is an actual restoration of primitive Christianity, as it existed under the Apostles in the first century A.D.

...what if we find that the doctrines Joseph Smith restored were, indeed, legitimate early Christian beliefs and practices from the first two or three centuries after Christ? If Joseph Smith taught doctrines that are in harmony with those of the early church but which were essentially unknown in his time, the skeptic must provide an explanation for the phenomenon. We shall see that the Prophet did restore legitimate early Christian doctrines, many of which can be shown to have preceded the present doctrines of the mainline Christian denominations–and he did so in the absence of much of the primary data available today. How could this have happened? If Joseph Smith’s explanation does not suffice, some other explanation must be put forth.

(Later, in the Conclusions page of the Restoration series from FAIR)

Had Joseph Smith created a church which differed from the other churches of his day and which had no relation to what we now know of the primitive church, his claim to be a restorer would be blatantly fraudulent, but since support for his teachings and ideas is so abundant from early documents, not in a general way, but in numerous specifics, one has to conclude that there was some source other than his own imagination for these striking parallels.

Early church father quotes: http://www.earlychristiandictionary.com/Veil.html

BYU:

"Most Christians in Corinth, regardless of their background, would have had similar feelings about the hair and veiling of women. Long hair was an expected sign of femininity, and covering it could be a sign of modesty and reverence, while cutting it was a sign of disgrace."

Cited from Eric Huntsman:
Eric D. Huntsman, “‘The Wisdom of Men’: Greek Philosophy, Corinthian Behavior, and the Teachings of Paul,” Shedding Light on the New Testament: Acts–Revelation, ed. Ray L. Huntington, Frank F. Judd Jr., and David M. Whitchurch (Provo, UT: Religious Studies Center, Brigham Young University, 2009), 67–97.