The word is used to describe a homoerotic or homoromantic subtext between two characters, generally on a television show. Where one sees HoYay is, of course, extremely subjective, though in some cases it can be canon, not just subtext
Ok, so that said, I will take a quick stab at it: (will ponder more and feel free to ask other questions)
Can't you have a good friend that meets you for lunch etc...without being in love with you or other women?
Sure. But add to the mix helping Jackie hide her affair, assisting her drug addiction and stealing Jackie's bills off the kitchen table and I think sheís crossed into Ho Yay! Territory. Then, spending the night, which it appeared it had not been the first time, and my gaydar is dinging madly. And sometimes it's just the way O'Hara looks...like she wants to say more, feel more, be more to Jackie.
In my mind, OíHara is more like the side kick in love with the main character or the main character's girl.
Admittedly, Ho Yay! is often little more than wishful thinking and is more a habit of sorts from folks my age, whoís only gay characters for years on screen of any size were in their imagination.
But Ho Yay! is subjective and if you donít see it, you donít. We all have ideas of what direction we want our favorite characters to go. You may want OíHara in bed with a hot guy while I would want her in bed with me. :-) And ultimately, itís up to TPTB as to where she ends up.
Finally, Iím not sure what you mean about the 25th birthday thing, so Iíll have to wait for you to expand, but if you mean the fact that she had a boyfriend at 25, that doesnít mean anything. Lesbians aren't man haters, for the most part. (Some of my best friends are men! Ha!) And I personally know plenty of women who have come out in their 30ís, 40ís and 50ís. And there are probably plenty who come out older, or never come out at all.
Hope this answers some of your questions or at least will start the conversation.