The Council, the ones whose personalities we see aside from Velcinda and Parqual, seem to be in rough agreement - in fact, the entire Council itself was created largely by Velcinda and her tending to the day-to-day maintenance of the Forsaken populace as an apothecary. Nathanos is trying to mollify his queen, and while he's technically correct in that they're all not in lock-step with one another (obviously), he's still understating the current that represents soft opposition to Sylvanas' goals for the Forsaken. I've no doubt Sylvanas was still secure in her position, and could've overrode the Council with clever politicking, but she wasn't really in a position to do that due to the needs of the greater Horde as well as her own plans being set into motion.
No, it would've been more "we acted without direct sanction from the High King, and our actions neither represent the position of the Alliance nor should be construed as Alliance policy toward the Forsaken or Sylvanas." Which, both literally and figuratively, is actually true of the Alliance position at the time, as you yourself have been at pains to establish elsewhere.
Unknown, but I would imagine it would be more than eight considering the numbers of Quillboar he knew he was going up against. I would assume a hefty battalion of them, at the least. Garrosh's thoughts don't matter - I just wanted to draw up a parallel between an Alliance near-defeat in the fact of an otherwise underestimated enemy (the Gnolls) and the same scenario for the Horde. If a similar thing can happen to the mighty and often-victorious Horde army, then it should be understandable for the Alliance as well.
See above.
Sorry, that was meant as a humorous aside, not the substance of the riposte. America in the early 20th century didn't do much in the way of growing (similar to Stormwind prior to the Gnoll Wars) - we were still establishing ties, and mostly staying out of global conflicts due to our rough starts with the War of 1812, the Civil War, Spanish–American War, and the various smaller conflicts interspersed throughout the 19th century. World War I and II were what really kickstarted our industry, especially in the fields of defense and military technology. Similar to Stormwind (and probably the history on which Stormwind is loosely based), the Gnoll War lit the fire of expansionism in the previously small kingdom, bringing it new territory and new size, and of course into new conflicts. I mean, America nearly tore itself apart in its early days, without the aid of an external force beating down its doors. Obviously it (like Stormwind) recuperated and went on to thrive just fine.
The Gnoll Wars were a close thing for Stormwind, no doubt about that - but regardless, they faced down the threat and were victorious. They won the battle, and in so doing they went on to claim new territories and grow as a nation.
Specifically:
"The final provocation came when Prince Llane Wrynn personally led a small party to strike at the Gurubashi leadership in central Stranglethorn, which succeeded in uniting the trolls against Stormwind. Though costly and close-run, the human kingdom eventually emerged victorious, largely due to the intervention of the Guardian Medivh.
With the entire troll army completely destroyed or routed at the gates of Stormwind City, the jungle trolls of the south would never succeed in threatening the kingdom again. The war's conclusion also marked the beginning of nearly two decades of relative peace for Stormwind, to be eventually interrupted by the onset of the First War against the Orcish Horde."
Stormwind spent those days of peace before the First War strengthening their nation and growing outward, which is what they had been previously doing.