I think I've found the Battle Pike wilds. I say think, because despite the fact I have edited them in a hex editor (and multiple hex editors showing the changes), I personally can't get any changes to show up in-game. I'm only really posting these because they make sense compared to what's shown on the Bulbapedia page, and maybe somebody else can help out with this to say if they get results, if this is somehow completely wrong, or if it's just VBA getting tired of allowing me to have nice things.
Spoiler:
Pike wilds start at 0x6121D4 for (Level 50?) and 0x612274 for (Open Level?). There are twelve entries followed by four pointers on the first one splitting them into four blocks of three, and then twelve entries followed by six pointers on the second one, the first four pointers splitting the previous twelve entries into four blocks of three and the final two pointing towards the first and second sets of pointers. The format for the wilds itself is a 12 byte data structure:
7B 01 | 04 00 | 5C 00 89 00 22 00 BC 00
1) Species, 2 bytes
2) ???, 2 bytes
3) Movepool, 8 bytes
Displayed is the generic Seviper entry. Its movepool is Toxic, Glare, Body Slam, and Sludge Bomb. I'm not sure what the ??? is, but it's either 04 00 or 05 00, and has been noted in the spawn listing alongside what Bulbapedia states is its spawn rate.
Set one (Rooms 0~280)
Seviper 04 00 26%
Milotic 04 00 26%
Dusclops 05 00 48%
Set two (Rooms 281~560)
Seviper 04 00 26%
Milotic 04 00 26%
Electrode 05 00 48%
Set three (Rooms 561~840)
Seviper 04 00 26%
Milotic 04 00 26%
Breloom 05 00 48%
Set four (Rooms 840+)
Seviper 04 00 26%
Milotic 04 00 26%
Wobbuffet 05 00 48%
Each instance of Seviper and Milotic is its own entry, so they should be customizable to the hacker's whims. The entries in Open Level are the same, but have slightly different movepools.
It'd be nice if these actually were the offsets though, because then after that it's figuring out what determines the Pokemon selected by each facility. Outside of the list being a in a "general sliding scale of difficulty" there's not really much other leads on selection.