Trumpet of Doom

"3 months from now"... *counts on fingers* September, October, November, December... Jan, are you zero-indexing something that doesn't need to be? Seriously, though, take all the time you need.

Try running it as an administrator?

The first post of the thread for the modpack (here) tells you which mods cause problems in the Safari Zone.

Really, there's only about two mods from the pack that you need to take out to make the Safari Zone encounters not crash. You can totally have the Wild Encounter Rates mod running, and it'll make it much easier to find the rare mons.

Right-click (or Ctrl-click) on the app and choose "Show Package Contents" from the menu that pops up, then enter the Contents folder, then Resources. After that, follow the Windows directions as written.

What worked for me to beat his Hawlucha was a Sturdy Aggron (if you caught an Aron earlier) with Metal Burst. If you have a Gale Wings Talonflame with Acrobatics or a Pink Nectar'd Oricorio with Revelation Dance, those may also help, though I don't think you can catch either of those at this point in the game if you don't already have them. Flying Press should do more damage with a Fist Plate, yes.

Yep!

Remember that Pikachu evolves with a Thunder Stone, not by level-up.

This is apparently a known issue with Pokémon Essentials. The latest Reborn dev blog is entirely about it; I would assume the Reborn devs are going to pass the fix along to the Rejuv devs, but I cannot say so with any authority.

Is it possible to get items off wild Pokemon in Goldenwood Park? There's nothing listed, but Poliwhirl theoretically carries King's Rocks.

Having run into the same problem, this doesn't seem to work.

~/Library/Application Support/Pokemon Reborn (Library may be a hidden folder in your user directory.)