Hostilities against any group of players, formal or informal, has never been considered harrassment in the past, so unless CCP wants to change their policy, this is firmly black and white, non-harassment even if you follow them from system to system.
There are some qualifications of course, CCP has been deliberately vague on what actually constitutes harrassment. Past precedent seems to be that any in-game, in-space actions are fine and you only run into trouble when any smacktalk or verbal taunting or antagonism goes beyond the context of the game, into real-world stuff.
A petition for clarification would give you a more definitive answer, GMs rarely weigh in in a forum thread like this.
I’m greatly enjoying this story, Xuixien, keep doing what you do. I’ll be munching popcorn over here in the corner. Oh and yes, scooping a citadel that doesn’t belong to you in highsec does make you a suspect, I found that one out myself not long ago.