The modifier names in the data file generally can't be a suffix of any other name: "Combat Mana Cost: <expr>" would match the regexp that looks for "Mana Cost: <expr>", for example.
Yes, and in fact that was done with the "Spell Damage" modifier to distinguish it from "Hot Spell Damage", etc., but there would be performance implications for doing this in general. In Java at least, a regexp starting with at least four characters of literal text is vastly more efficient because some optimization tricks can be done to quickly skip over parts of the string where the pattern cannot possibly match; a regexp with any sort of variable matching at or near the start has to examine every single character in the string (possibly multiple times) to check for a match.Couldn't you add "(?:\t|, )" to the front of the regexp (or middle, where ever the case may be) to match things exactly, allowing you to make modifiers.txt more consistent with Display Names?