making anyone editable is as simple as using this gameshark code:

811502C6 0200

but what makes it tick?

values of 0x0100 and 0x0200 make it work.
-----------------------------------------
on reading it with The Dwayne Johnson:

LBU V0 0x0CC6 (T0) ; [V0 01] from 801502C6 (T0 is 8014F600)
SLTIU V0 V0 0x01 ; [V0 00]
LUI AT 0x8017
SB V0 0xEED8 (AT); 8016EED8: [V0 00]
ANDI V0 V0 0xFF; [V0 00]
BEQ V0 R0 8010C0D0 ; takes branch
ADDU A0 = R0;

ADDIU A1 R0 0x4A
ADDIU A2 R0 0x12 ; as opposed to 0x13 (see PC 8010C0C4)
ADDIU A3 R0 0x05 ; as opposed to 0x0A (see PC 8010C0CC which runs after a jump)
SW R0 0x10 (SP); 8008E508: 0
JAL 80141ED4 ; takes jump
SW R0 0x14 (SP); 8008E50C: 0

ADDIU SP SP 0xFFC8 ; [SP 8008E4C0]
stack pointer fuckery.
by now everything is said and done.

________________________________________

and now with a Created Wrestler:

LBU V0 0x0CC6 (T0) ; [V0 02] from 801502C6 (T0 is 8014F600)
SLTIU V0 V0 0x01 ; [V0 00]
LUI AT 0x8017
SB V0 0xEED8 (AT); 8016EED8: [V0 00]
ANDI V0 V0 0xFF; [V0 00]
BEQ V0 R0 8010C0D0 ; takes branch
ADDU A0 = R0;

ADDIU A1 R0 0x4A
ADDIU A2 R0 0x12
ADDIU A3 R0 0x05
SW R0 0x10 (SP); 8008E508: 0
JAL 80141ED4 ; takes jump
SW R0 0x14 (SP); 8008E50C: 0

ADDIU SP SP 0xFFC8 ; [SP 8008E4C0]
stack pointer fuckery.
by now everything is said and done.

________________________________________

let's write to it with a caw

PC is 8000796C

zeroing it out. next press of go yields

SH V0 (S0); 801502C4: [V0 02]
ADDIU V0 A0 0x1; [V0 37]
ADDU A0 V0 R0 ; [A0 37] (was 36 before this)
SLL V0 V0 0x10 ; [V0 00370000]
SRA V0 V0 0x10 ; [V0 00000037]
SLTI V0 V0 0x37 ; [V0 00] <-- this seems like a check.
BNEZ V0 800079AC ; no jump
ADDIU S0 S0 0x02 ; [S0 801502C6]
LW RA 0x54 (SP) ; [RA 80005FB8] from 8008E55C
LW S0 0x50 (SP) ; [S0 80323FA8] from 8008E558
JR RA
ADDIU SP SP 0x58; [SP 8008E560]

ADDU A0 S0 R0 ; [A0 80323FA8]
ADDU A1 S2 R0 ; [A1 8014FB80]
JAL 8000766C
ADDU A2 S1 R0 ; [A2 80150258]

stack pointer storage stuff. hitting go. (this was a bad idea)

PC is now 8012156C

SB V0 0x0CC6 (S0) ; 801502C6: [V0 02] <- we seem to be writing to the best place!
LW A0 0x0258 (S0) ; [A0 0A01] from 8014F858 <- wrestler ID4
JAL 8011FDE0
LW A1 0x025C (S0) ; [A1 00000000] from 8014F85C

ADDIU V0 R0 0x01
LUI AT 0x8015
SB V0 0x1B2C (AT) ; 80151B2C: [V0 01]
LUI AT 0x8015
SW A0 0x1B30 (AT) ; 80151B30: [A0 0A01]
LUI AT 0x8015
JR RA ; (8012157C)
SW A1 0x1B34 (AT) ; 80151B34: [A1 00]

and that's it for that one.

________________________________________

writing to it with das rock; PC is 8000796C again.
zeroing it out. next press of go yields PC 80007E98,
most of which seems the same.

SH V0 (S0); 801502C4: [V0 0001]
ADDIU V0 A0 0x1; [V0 37]
ADDU A0 V0 R0 ; [A0 37]
SLL V0 V0 0x10 ; [V0 00370000]
SRA V0 V0 0x10 ; [V0 00000037]
SLTI V0 V0 0x37 ; [V0 00]
BNEZ V0 800079AC ; no jump
ADDIU S0 S0 0x02 ; [S0 801502C6]
LW RA 0x54 (SP) ; [RA 80005FB8] from 8008E55C
LW S0 0x50 (SP) ; [S0 80323FA8] from 8008E558
JR RA
ADDIU SP SP 0x58; [SP 8008E560]

ADDU A0 S0 R0 ; [A0 803209A8] <- this changed.
ADDU A1 S2 R0 ; [A1 8014FB80]
JAL 8000766C
ADDU A2 S1 R0 ; [A2 80150258]

stack pointer storage stuff. hitting go. (this was a bad idea)

PC is now 8012156C

SB V0 0x0CC6 (S0) ; 801502C6: [V0 01] <- we seem to be writing to the best place!
LW A0 0x0258 (S0) ; [A0 0001] from 8014F858 <- wrestler ID4
JAL 8011FDE0
LW A1 0x025C (S0) ; [A1 00000000] from 8014F85C

ADDIU V0 R0 0x01
LUI AT 0x8015
SB V0 0x1B2C (AT) ; 80151B2C: [V0 01]
LUI AT 0x8015
SW A0 0x1B30 (AT) ; 80151B30: [A0 0001]
LUI AT 0x8015
JR RA ; (8012157C)
SW A1 0x1B34 (AT) ; 80151B34: [A1 00]

________________________________________

at this point I want to see how V0 gets written at 8012156C.

PC 80121568
ADDIU V0 R0 0x02 ; [V0 02]

apparently we've come across a branch here.

going backwards, PC 8012155C
SLTI V0 V0 0x0A00 ; [V0 00000A01] -> [V0 01] ; the check to see if it's a CAW.