I think that's a problem all muns with an asocial, stalker-ish character run into, and I imagine it'd be especially difficult if it's your only character and you're therefore unable to be as active as you may want to be. For what it's worth, I think you play a great Sei, so my only advice to help with interaction would be to try to let him just randomly run into characters around Kiseki rather than initiate conversations. And I don't think you need to worry about commenting on hackable entries and action logs; if the mun doesn't want certain characters to comment, they'll likely lock the post either completely or make it viewable to specific characters only, or somehow otherwise specify their preferences in an ooc note. Interacting with all kinds of different characters is kind of the point of the game, after all.