I'm sorry, it is tragic that Tester gets in the way of Kadsey's relationship, it's just something to deal with (which is another reason why Red Ashton has better ending~) However I am very happy to read (or write) fanfictions where Ash and Kads are happily together!
But those are really good questions!! It may sound strange since I'm the one who made it but there are some things I just didn't think about or might not make sense because most of the story was thought up AFTER the first game was finished!
So the story in my mind is that when Ashton finds out he and his would aren't real (and that the person who created him did so after a weird yandere golfball) he was beyond upset and going through a kind of crisis. I don't remember if I wrote it anywhere but he started to really isolate himself from his friends, seeing them as just game characters. Then in his darkest moment he not only connects to the player's computer but is able to hack into their private files and kind of get to know them. I wanted it to be vague and depend on the person as to what Ash sees in them (hence why he calls them talented because that could be for anything), but the biggest reason is that yes the Tester is real.
I'm sure I said this SOMEWHERE but at first Ashton saw the tester as a prize to be won, since he's always felt like a loser and very self conscious of himself, and the tester was the one thing he could win, but then after the date he starts to realize he really wants to be with tester somehow. If that makes sense.
But if Tester plays after Kadsey had confessed to Ashton?! And assuming Kadsey either helped him cope with not being real or that hadn't happened yet, hmmmm that IS interesting! So this isn't something I've pondered so I hope it's not too out of character but I don't think Ashton would fall in love with the Tester, I think he'd be more curious about the real world and want to find a way for you all to get together platonically. But like I said that's just off the top of my head. I imagine Ash would be very loyal. Thank you again for liking my game!! I am so incredibly proud of it!!