When ITC was a separate company, they licensed their trademarked font names and provided analog artwork to many different companies. Each one remaining into the modern era produced a slightly different digital version and new companies, like Adobe, added their own digital versions of these as well.

Addressing the individual differences would take a few whiles, but in general, the core set of glyphs should match from vendor to vendor except perhaps for the scaling to the font to the em. And, glyphs like Euro, which were added after the original artwork was distributed, may not be consistent.

The differences between Std, Pro and Com are usually in language support. Sometimes Pro fonts also incluse advances typographic features like smallcaps, alternates, swashes, etc. Check the glyphs tab in MyFonts to see the amount of glyphs. You also can see what features and character set each font as when you check tech specs, which can be found by clicking on one font: you then get a waterfall preview, with for tabs above it.

Is it possible the Adobe version has a more lenient EULA (like concerning embedding, modification, etc.)? If so, go for that one.

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Is it possible the Adobe version has a more lenient EULA (like concerning embedding, modification, etc.)?

Looking through the list of additional license rights for Adobe fonts, the ITC fonts are all listed as, "1 : Licensed for print and preview embedding" in a list of criteria that also includes:

2 : Licensed for editable embedding
3 : Licensed for modification
4 : Licensed for users who directly license DPS
5 : Licensed open-source fonts