Nope. FDF mod makes ALL hints show up in blue, even for example ones in missions you have made (without putting in any special characters). They change things in the game's config that changes the hint color. This makes ALL hints show up that color, so they still have single-color hints, like everything else.
As for a 'tab code', you can just put in a few spaces yourself. Any more than like 3 spaces looks bad anyway.
I'm not entirely sure about your last question, but do you mean a code that would only display, say, the first 3 digits of a variable? In that case, you can easily accomplish that via scripting/math.