In case anyone is interested, I've worked out the problems I was having.
Some of the problems were fixed with the DIV & float declarations (that took care of Firefox), some were caused by my lack of understanding of the PRE- and PRE-WRAP text formatting statements (trying to let the Rich Text in the list display as formatted in the list.) Safari continued to have extra space in the middle column before the "Arrangement Description" paragraph. I spun my gears for a long time trying to fix it with the FLOAT because it looked like something from column 1 was "bumping" column 2. I finally started swapping out data fields one at a time - putting in placeholder text - until I found that getting rid of the "Arrangement Description" field fixed the problem. That is one of the fields that have rich text, so then I focosed on the declaration for that paragraph formatting.
It sure is interesting how the different browsers have different tolerances! The modified declarations in my stylesheet section are:
.SongTitle{FONT-SIZE: 16pt; FONT-WEIGHT: bold;}
.Instrumentation{FONT-SIZE: 10pt;}
.ArrangementDescription{FONT-SIZE: 12pt; LINE-HEIGHT: 1.25em;}
#SeriesWrap { WIDTH: 11.0in; }
#SeriesHeader {FONT-SIZE: 200%; FONT-WEIGHT: 900; BACKGROUND-COLOR: #2d73b9;
COLOR: WHITE; TEXT-ALIGN: Center; WIDTH: 100%;}
#ArrangementWrap {WIDTH: 100%;}
#Detail {FONT-SIZE: 100%; WIDTH: 100%;}
#NestedDetail {float: left; WIDTH: 7.5in; MARGIN-RIGHT: 0.5in; }
#Column1{float: left; WIDTH: 1in; margin: 6pt .1in 0 0;}
#Column2{margin: 6pt .1in 0 1.25in; }
#RemainderDetail{ }
#Column3{Margin: 6pt .1in 0 0; PADDING-LEFT: 2em; TEXT-INDENT: -2em; }
#Footer{clear: both; 100%; MARGIN-TOP: 12pt; LINE-HEIGHT: .5; BORDER-TOP: 1px solid silver;}