I'm going try to remain spoiler free in this and my other works. Though if you want to guess whose going to appear, feel free. However, i'm not going to confirm or deny these 'theories' so be aware of that.
Very cool but Vinyls eyes are the wrong color. I know the fandom has her with red eyes but in the show here eyes are shown at one point for a very brief moment (I think it was A Canterlot wedding part 2 I'm not sure) and her eyes are pink.
I like red better myself but weather you change them or not is up to you. I like them either way.