1. Tifa;

2. Tifa;

3. I think it won't have any effect whatsoever.

I wasn't rude with Aerith when I first met her, quite the contrary. I did all of the side quests. I spoke with Tifa first before fighting with Abzu. I didn't know at the time that my choices would have any influence, but I'm glad my scene was with her. I like Aerith too, but I prefer the idea of romance between Tifa and Cloud!