I typed the words "gay" "lesbian" and "homosexual" into the file that Martin sent us, and Mandy is the first occurence of these words.
However, since there doesn't appear to be many character descripts for the episodes between 1991 and 1995, there may have been a small storyline that occurred in that period.
Charlotte's first appearance I think was some random scene in Jude's houses, she was living upstairs, where she wanted some coffee or something. Her main entrance storyline was as the trainee nurse that saved Jude's life.
After Sally fell out with Shauna and she left the bay, and then Gypsy moved in with Will, both Sally and Charlotte were living in houses on their own, and so they decided that it was a good idea for them to move in together.
Noah's first appearance was just before the mudslide as some random biker who picked Hayley up at a nightclub.
Jude's first appearance/entrance storyline I think was just as Noah's brtoher who was cleaning the school, there was nothing big or dramatic about it.
You're right about Josh's leaving storyline.
Dani and Josh split up after having an argument in the 2002 Season Finale. I think it was something pretty small they were arguing over.