trainer format

Trainer table starts at x23EAF0 in FR. Entries are 40 (x28) bytes long.

0x0 - Byte. Controls how much Pokemon data there is- 0 for default movesets, 1 for custom movesets, 2 for custom items, 3 for both.
0x1 - Byte. Determines trainer's title. Note that in FR there are many duplicate titles that are holdovers from RSE.
0x2 - Byte. If highest bit is set, the trainer's pokemon will be female if their gender ratio is 50%. Other bits influence intro music (and something else?)
0x3 - Byte. Determines trainer's sprite.
0x4 - Twelve bytes, Trainer's name. Limited to nine chars + terminator IIRC. Not sure what last two are for.
0x10 - Half-word. Trainer's first usable item.
0x12 - Ditto, second item
0x14 - third item
0x16 - fourth item
0x18 - Word. Indicates if double battle.
0x1C - Word. Actual AI strength- marked as Unknown in A-Trainer. Zero appears to be mostly random, 1 is better but makes mistakes often, 7 plays as well as the AI is capable of. Some trainers in Emerald (Winona) have oddball values that need looked at. The per-Pokemon values marked as AI control IVs.
0x20 - Word. Indicates number of Pokemon a trainer has.
0x24 - Word. Pointer to the actual Pokemon data.

The actual pokemon data, for trainers who have custom movesets+items:

0x0 - Half-word. IVs, misidentified by A-Trainer as "AI Value". floor((Value+1)/8) is given to all stats, I think. Only one byte is used.
*If using the EV hack, this is where you select the spread used.
0x2 - Half-word, level.
0x4 - Half-word, species.
0x6 - Hold item, 0x0 for nothing.
0x8 - Half-word, first attack.
0xA - Half-word, second attack.
0xC - ditto third
0xE - ditto fourth

Other trainer types (determined by first byte) have the data structured differently.