1 - Yes, the story will influence character look in some ways, aside from that there will be major character development due to events in storyline.
2 - Lots of details will be connected to either main storyline or world building. I plan to make extensive use of environmental storytelling and put a lot of small details into character's dialouges, I even consider adding some dialouge options which would serve for additional, more detailed information for the player for those who are interested.
3 - The game is planned to be around 4-6 hours at least, might even hit the 8 hour mark but I can't guarantee that.
I plan to have some replayability with some freedom of exploration, optional world detail to discover and even some secret areas.