No problem and indeed, I seems to be set around that period. Of course the height of the Irish Brigade's success was under him and shortly after at Fredericksburg, though still a solid force by Gettysburg, their ranks were much depleted and Thomas Meagher was gone, so some of the luster was gone too. But God Bless Father Corby, as he would absolve the lads of the Emerald Isle for their sins before they went to fight. Like most of the famous "styled units" by the end f the war, most were gone or decimated, as was the pageantry and romance for the war too.
The mention of the dates, is actually a part of the quote, I quoted the full text, not just the famous verse of it. I do agree with you that Grant has those few skills needed in such a time and there are few who could be at the same level as him in those regards. I think Sherman's other famous quote speaks to that characters well:
"I am a damned sight smarter man than Grant. I know more about military history, strategy, and grand tactics than he does. I know more about supply, administration, and everything else than he does. I'll tell you where he beats me though and where he beats the world. He doesn't give a damn about what the enemy does out of his sight, but it scares me like hell. … I am more nervous than he is. I am more likely to change my orders or to countermarch my command than he is. He uses such information as he has according to his best judgment; he issues his orders and does his level best to carry them out without much reference to what is going on about him and, so far, experience seems to have fully justified him."
To win a war like this you need different characters at different levels and the Union was able to find them as the war went on and the South was able to lose them just as well or not promote them because of patronage, favorites or bigotry. Don't get me wrong, I know I am a CSA officer in the Club, but the CSA had so many more problems as the war went on, that Union had too, but managed to mitigate. The blame falls with many and both sides, not just with those who individuals here and in the textbook like to use as the scapegoats. Despite what people may feel here, there are no marble men from this War or any war.
I am a big supporter of Thomas by the way. Often overlooked, but in those times that mattered, he got the job done, that so many couldn't do the way he did. I do agree with you, many of these men would of been forgotten had the war not happened. Lincoln might of been a good Senator in Congress, Lee may have risen to Governor of VA and Grant would of been known for the best saddles in Galena. But fate propelled them to the heights of humanity.
I have always loved what Shelby Foote said of Grant: ""Grant the general had many qualities but he had a thing that's very necessary for a great general. He had what they call "four o'clock in the morning courage." You could wake him up at four o'clock in the morning and tell him they had just turned his right flank and he would be as cool as a cucumber."
Also: "Grant, after that first night in the Wilderness, went to his tent, broke down, and cried very hard. Some of the staff members said they'd never seen a man so unstrung. Well, he didn't cry until the battle was over, and he wasn't crying when it began again the next day. It just shows you the tension that he lived with without letting it affect him"....."Grant, he's wonderful."
I think one of the big reasons why so many people are drawn to this conflict, as we see ourselves and our own personal struggles in so many of these men, maybe not just one, but maybe many of them. That they give hope in times of darkness. That's what history is all about.

Me gots another Irish Brigade song for you all

"The Irish Volunteer" - sung by David Kincaid
http://www.youtube.com/watch?v=yavz9rzaOSY