I'm not really a fan of the Choice items to be honest, I'd perfer the Expert Belt for more power on Super Effectives, Power on many moves is much better then power on only one move.
I like your banner at the start, it looks great!
I also noticed that there were questions at the start as well, sorry about that:
What do you think about the Latis' shiny forms compared to their regular colour?
Latias with Yellow does look very good on her as many other people have noted, but a Green Latios is very underrated, I personally like the look, but I guess many people compare him to his shiny sister that doesn't make him look as good because of how spectacular she does.
What would be the Latis' favorite genre of videogames?
I've pictured Latias the type that does the cute type of games, maybe the Party type, you know like Mario Party and Guitar Hero. While her brother is one for action and strategy games.
Latios and Latias end up in a String group which instruments should they play?
Latias is a Harp player, Latios a Double Bass player