The fact that Shane is the one giving Hana a very enthusiastic talk on strategy seems a bit odd for his character at first, but it turns out that he's actually giving the player a tutorial on how some of the choices in the game to get the best endings are not always obvious. Considering that his route is considered the hardest one, and uses the themes he talks about in spades, it's not as surprising that they would use him to drill these thoughts into the player's mind.
If Hana chooses to go to the Flower Festival with Jared, Mai is immediately crushed and saddened by her choice. Knowing that Mai is very Genre Savvy, that means she already knows from Hana's choice that she will inevitably end up dating him, and that there's nothing that she is able to do.
Mai is essentially a main character in the game, being easily the most prominent character besides Hana and whatever guy you end up dating. Yet at the end of almost every route, she's nowhere to be found - she doesn't attend the tournament, and typically isn't seen or even mentioned in the post-tournament scenes. When you think about it, this marks Character Development for Hana, assuming you get a good or best end - at the start of the game, and throughout its majority, Hana depends largely on Mai for help. At the end, Mai isn't around because Hana no longer needs someone to lean on, or at the very least is now able to lean on her new boyfriend.
Almost everyone goes for the PBG route, or at least likes it the most, particularly because it's very easy. When you think about it, PBG's route can actually be considered the "best" route, in terms of its ending: Hana and PBG, once best friends, are once again together and even in a relationship; Mai gets together with Jared, the boy of her dreams, who apparently now reciprocates her feelings; and everyone else's problems - Jon losing Jacques, Jared's issues with his mother, etc - are ones that the guys can probably overcome and figure out without dating Hana; using those examples, Satch can repair Jacques once he knows about him being broken, and Jared will probably call out his mother the same way he does in his route now that he's with Mai. When you think about it, in PBG's route, at least with the best ending, few people - if any - are left unsatisfied.
There's no Mai route because if Hana dated Mai, joining the Normal Boots Club would suddenly become a lot less important in her eyes (especially since Mai seems largely apathetic towards gaming), meaning both the Normal Boots characters and the tournament would all be Demoted to Extra.
On the PBG route, when he flubs during a soccer game, a student named McJones is the one to take him to the bench. Seems out of place for the captain of the team to be benched by a player, but if you watch PBG's Hardcore series, you'd recognize McJones as being the alias of PBG's older brother, Stewart. Assuming that carries over to the game, it comes across less like an annoyed player benching his captain and more like a brother stepping in to help out when his younger brother seems out of sorts.
In a bit of a comedic way, there are a lot of parallels between the soccer games and PBG's Hardcore series. The soccer team consists of PBG and Jeff, as well as unseen characters Dean and McJones, all four being from the Hardcore series (we don't really know who else is on the team). PBG is the captain of the soccer team and the one who runs the Hardcore series. Dean is mentioned as being not good in dangerous situations, which is also accurate to how he is in Hardcore. PBG takes the soccer team very seriously, like he does surviving in Hardcore. The soccer team seems to be PBG's main priority and thus what he's known for throughout his route, like how the Hardcore series is widely considered his best and most popular ongoing work. And an injury removes PBG from the soccer team for the rest of the season, like how being killed in Hardcore takes one out of the season.
At the end of the Shane route (best ending) Hana attends the tournament on a Saturday morning. The next day she and Shane hang out. That evening he says that tomorrow is Sunday. Apparently there was either a day between Saturday and Sunday or maybe their Sunday just happened twice?
