I'm good with Edelweiss III and Edelweiss IV although we might be better served by using numerals instead; (think Edelweiss 3 and Edelwiess 4). My issue here is that with this many iterations, we're running out of four character abbreviations for each version.
2,500 years ago people worshiped cats. The cats have never forgotten this!
Based on the 'box back' section, I would vote for Edelweiss - Book. Its predecessor would then remain Edelweiss - Expanded and the 'original' being simple Edelweiss. Otherwise leave out the I, II, III, & IV as they seem a bit muddled.
... More and more, people around the world are coming to realize that the world is flat!