Rache

It's a bug, we're looking into it.

You need to have completed the full regional OT dex for the region you're trying to claim the patch from, you don't need to fill the entire national dex unless you want them from all 4 regions. OT is the requirement instead of owned to prevent them from being easily farmed by making new accounts then trading with yourself.

She's permanent, yes.

They have those species in BDSP's Battle Tower. They use them alongside their ace and something else that matches their gym's type, so I'm inclined to believe that they aren't rentals and that the leader owns them. Rematches pull from all canons to make them a bit more challenging, so these species were no less suitable than the generous amount of non-matching ones the Kanto leaders have been seen with over the years. A lot of teams were shuffled around to account for the new additions, most Sinnoh leaders in the guide are inaccurate at the time of posting this.

Hidden abilities obtained via breeding today were unintentional, the mechanic is currently being fixed. The ones that exist will also be set back to their normal abilities.

This is a fair point. For randoms only, next update we'll reduce the penalty for losing to someone significantly below your ELO due to the lack of teambuilding.

RNG is the same for every player and every type of battle. There are no "lucky" or "unlucky" accounts, and the odds are the same in matchmaking as they are everywhere else.

It's intentional, it's weighted to pull Hidden Power Psychic most of the time as that's its only potential STAB move. Making it less common would be a huge nerf to an already weak species. Occasionally it pulls Fighting or Bug despite the loss of power to make it slightly less predictable. These two types were chosen as they're each super effective against two of Dark / Psychic / Steel, the types that resist HP Psychic, making them the most likely types to hit something for super effective damage. If it pulled a random type instead, it would rarely be as punishing to switch in something that resists its most common move.

At some point I'll go through the existing sets and adjust some of the ones that are under-performing and remove any that I don't think are salvageable, I'll likely do this sometime after gen 5 species are added as a lot of builds will be better or worse in that meta. I'd prefer not to reduce a Pokemon's possible sets to only their best one unless absolutely necessary though, making them unpredictable was one of the major goals. For Beautifly, it has two builds, one with Quiver Dance and one with U-Turn. Their win rates are almost identical this month (48.99% vs 49.00%), so there's no reason to remove either of them, lv88 is appropriate for both. Cases where a single build on a Pokemon is much better than the rest are already mostly handled by the monthly level adjustments. If an individual build has a winrate over 54%, its level goes down regardless of how bad the rest of its builds are. As an example, Dragonite's best right now is its Dragon Dance set with a 55.51% winrate, ~4% higher than its second best set. The average winrate of its species is 48.29%, but if its DD set's winrate stays where it is, it'll still be reduced to lv72 next month. Its worst set is its support-focused one with a 42.93% winrate, it's gotten a lot worse over time due to the level reductions resulting from its better sets so it would be a good candidate for adjustment or removal later on if it stays this poor. We can potentially guarantee that teams facing Shedinja have at least one way to beat it, but we won't be removing the species entirely, losing sometimes due to poor matchup is an intended part of the format. Shedinja should become less common as more species are introduced though, the rest of gen 4 will be coming next update.

You're encountering moves like Fire Blast and Blizzard at this stage of the game because it's the gimmick of the Gamer and PI trainer classes. They use high-risk high-reward moves which do a lot of damage or have powerful effects if they hit, but are very prone to missing. Different types of trainers fight in different ways in this game to add some variety and difficulty to battles that are otherwise extremely predictable and easy to steamroll in the originals.

Night Shade should bypass Wonder Guard due to its typing despite not including a super effective message. It's an actual issue that's been fixed for the next update.

Some trainer classes have themes / gimmicks for their items and movesets. Harlequins and Clowns have their teams hold Air Balloons, just as Hikers have HM moves and Breeders have breeding-related held items.