Slots are relative--ie, leaving the first "slot" open on the status screen will not skip "slot1" in battle--
the character in "slot2" (or 3, etc.) on the status screen will then be "slot1" in battle.

Each section of in-battle stats is 0x204 (516) bytes long. This is an attempt to decode those bytes.

1D824/1DA28/1DC2C/1DE30/1E034 - PCs
1E238/1E43C/1E640/1E844/1EA48 - ??
1EC4C/1EE50/1F054/1F258/1F45C - Monsters
1F660/1F864/1FA68/1FC6C/1FE70 - ??

00-01: Current HP
02-03: ???
04-05: BaseHP?
06-07: ???
08-09: Max HP
0A-0B: ???
0C-0D: Current LP
0E-0F: Max LP
10-11: Current WP
12-13: Max WP
14-15: Current JP
16-17: Max JP
18-25: ???
26-27: Status (see below)
28-37: ???
38: Total Str
39: Total Qui
3A: Total Int
3B: Total Wil
3C: Total Psy
3D: Total Vit
3E: Total Cha
3F: ???
40: Base Str
41: Base Qui
42: Base Int
43: Base Wil
44: Base Psy
45: Base Vit
46: Base Cha
47: ???
48: Str mod (magic)
49: Qui mod (magic)
4A: Int mod (magic)
4B: Wil mod (magic)
4C: Psy mod (magic)
4D: Vit mod (magic)
4E: Cha mod (magic)
4F: ???
50: Str mod (equipment)
51: Qui mod (equipment)
52: Int mod (equipment)
53: Wil mod (equipment)
54: Psy mod (equipment)
55: Vit mod (equipment)
56: Cha mod (equipment)
57-58: ??? Seems 58 might have something to do with VictoryRune, went to 0D.
59: Something to do with LightSword, Shield, and the like, it seems. Also modified by equipment.
5A: Equipment weight.
5B: ???
5C-6B: Equipped Abilities
6C-8D: ???
8E-95: Equipment
96: RaySword hidden slot (see below)
97: LightSword hidden slot (see below)
98-B5: ???
B6-BD: Defense values (see below)
BE: Potentially something to do with armor, still testing this.
BF-204: ???

Status bit information:
1: Stasis?
2: Infinity--Magician Arcane effect?
   Does nothing if given to a character.
4: Sparkle--VMAX effect
8: Sparkle--SoulRune effect
10: Sparkle--Awakening effect
20: Blind
40: Stone
80: Venom
0100: Angry
0200: Charm
0400: Mess (Red)
0800: Mess (Yellow)
1000: Mess (Blue)
2000: Sleep
4000: Palsy
8000: Flat--Faint?
      Still alive, if HP>0

The RaySword/LightSword hidden slots work for any weapon you put there manually;
it's just that game code puts the appropriate weapon there when AlkaiserChange or LightSword is active.

Defense values:
B6: Slashing
B7: Blunt
B8: Piercing
B9: Fire
BA: Ice
BB: Electric
BC: Force/Light/Sonic
BD: Status
BE: ??