As I've been doing a Fakemon hack in Emerald, the Frontier was obviously a mess. Things weren't very well documented outside of the normal structures for the Tents and regular Pokemon (which is very well documented on Bulbapedia - for brevity they will not be discussed here, go to bulbapedia.bulbagarden.net/wiki/Battle_Frontier_data_structures_in_Generation_III if interested), but this still left things like the Brains and wild spawns in the Pyramid/Pike up in the air. After a bit of snooping around, I've found some stuff. I really doubt this warrants its own thread, so I'll put it here.
Frontier Brain info:
Spoiler:
The Frontier Brain teams are stored in a 20 Byte data structure, as shown:
41 00 | B3 00 | 18 | 0F | 6A/00/98/98/64/00 | 09 00/07 00/08 00/32 00
1) Species
2) Item (Normal indexing instead of Frontier indexing)
3) IVs (Apply to all stats)
4) Nature
5) EVs, in the order of HP/ATK/DEF/SPEED/SATK/SDEF
6) Movepool
Shown was Salon Maiden Anabel's Alakazam. It has a Modest nature, IVs of 24, an EV investment of 106 HP/152 DEF/152 SPD/100 SATK, and a movepool of Thunderpunch, Fire Punch, Ice Punch, and Disable. Its hold item is a Brightpowder.
Two things interesting to note is that Frontier Brains use normal item indexing instead of the Frontier's custom indexing, so they can hold whatever is wished for them to hold. Also, similarly to Steven's team in the Space Center event, they can have up to 255 EVs in each stat, and all EVs will be accounted for.
The teams themselves are located at the following offsets:
0x61156C, Salon Maiden Anabel
0x6115E4, Dome Ace Tucker
0x61165C, Palace Maven Spenser
0x6116D4, Arena Tycoon Greta
0x61174C, Metang, Skarmory, Aggron, Metang, Skarmory, Aggron*
0x6117C4, Pike Queen Lucy
0x61183C, Pyramid King Brandon
At each offset is six Pokemon. The first three Pokemon are used in the Silver symbol battle, and the next three Pokemon are used in the Gold symbol battle.
*This is two copies of Steven's team in the Space Center event - as Factory Head Noland uses random Pokemon from the Factory listing, he doesn't get a special team to use.
Battle Pyramid wild spawns:
Spoiler:
The format for the wild spawns is 12 bytes long:
61 01 | 23 | 02 | 56 00/D1 00/E3 00/00 00
1) Species
2) EVs, dictated by the normal Frontier EVing setup
3) ???
4) Movepool
I'm not quite sure what the ?? is, but it's 02 in every wild spawn entry.
Showcased here is a Pluslie with EV investment of HP/ATK/SDEF, and a movepool of Thunder Wave, Spark, and Encore.
As strange as it is to EV in Attack, it was most likely done to keep it from being too "bulky" as EVs in regular Frontier Pokemon are evenly distributed among each stat (in which case this is 170 in each stat, compared to 255 in both HP and SDEF)
The wild spawns themselves are located at 0x6126B0 for Level 50 and 0x612E80 for Open Level. At each offset is a master list of 160 Pokemon broken up into groups of eight, and then twenty pointers respective to which round it is pointing to. The list is virtually identical for Level 50 and Open Level, but the EVs are different in Open Level. A listing of the Pokemon in the Pyramid itself can be found at Bulbapedia, and it generally follows the order that the Pokemon are listed.
I haven't looked at the wild spawns in the Pike yet, but they probably share a similar format to the wilds in the Pyramid. Hopefully this can help out with Frontier hacking.