4. Good points. I'm on pins and needles, despite the fact that it seems that there is
really no substantial constitutional legal argument against marriage equality.
Like you said, under the auspices of the Constitution, it appears that everyone (LGBT or straight) simply has the unequivocal right to marry the consenting adult of their choice. End of story.
Even if I were straight, I would be extremely disturbed over the fact that I did not have the right to marry whichever consenting adult that I chose to marry, be they female, male, blue, atheist, whatever, etc. My point here is, the impending decision is relevant to everyone's rights, and not only specifically the rights of LGBT individuals.
The only problem I foresee is 5 conservative justices not having the ability, inherent or otherwise, to make a reasonably objective ruling on this issue. If they rule against equality, they are going to generally be seen as foolish, subjective, and incompetent, and will lose whatever smidgen of respect they have managed to salvage after the SCOTUS electoral debacle of 2000, particularly in the eyes of the majority of those who are knowledgeable in jurisprudence.