On way to avoid such ethical dilemmas is to start with an OpenSource font like my Jivita Typeface. The license allows you to make whatever modifications you wish, as long as you rename it, and as long as you release it under the same OpenSource license conditions. The GNU licence does not prevent you selling your version.
FontCreator uses a script to align diacritics in a nominally correct position. It may work for the Regular typeface without much further adjustment, but for an italic typeface or a handwritten script the user will always have to adjust the position manually. A knowledge of correct positioning is essential.
I developed and maintain the Complete Composites code for FontCreator. It is a plain text XML file that users can edit for themselves to add definitions, or modify the existing ones. I frequently make minor tweaks to the code. This is the definition for U Ogonek:-
<Composite><!-- U Ogonek -->
As you can see, it's fairly easy to understand. I use decimal code-points as I find them easier to understand at a glance than hex codes (which may also be used).