The One Man Adventuring Party™
01: Sorcerer / Ranger - +1 BAB +2 Fort, Ref, Will d8 HD 6+Int(x4) SP
02: Sorcerer / Cleric - +1 BAB +2 Fort, Will d8 HD 2+Int SP
03: Sorcerer / Cleric - +1 BAB +1 Ref d8 HD 2+Int SP
04: Sorcerer / Cleric - +1 BAB +1 Fort, Will d8 HD 2+Int SP
05: Mystic Theurge / Fighter - +1 BAB +2 Fort, Will d10 HD 2+Int SP
06: Mystic Theurge / Rogue - +1 BAB +1 Fort, +2 Ref, +1 Will d6 HD 8+Int SP
07: Mystic Theurge / Rogue - +1 BAB d6 HD 8+Int SP
08: Mystic Theurge / Rogue - +1 BAB +1 Ref, Will d6 HD 8+Int SP
09: Mystic Theurge / Fighter - +1 BAB +1 Ref d10 HD 2+Int SP
10: Mystic Theurge / Rogue - +1 BAB +1 Ref, Will d6 HD 8+Int SP
11: Mystic Theurge / Rogue - +1 BAB d6 HD 8+Int SP
12: Mystic Theurge / Rogue - +1 BAB +1 Fort, Ref, Will d6 HD 8+Int SP
13: Mystic Theurge / Fighter - +1 BAB d10 HD 2+Int SP
14: Mystic Theurge / Rogue - +1 BAB +1 Ref, Will d6 HD 8+Int SP
15: Arcane Trickster / Cleric - +1 BAB +2 Ref, Will d8 HD 4+Int SP
16: Arcane Trickster / Cleric - +1 BAB +1 Fort, Ref, Will d8 HD 4+ Int SP
17: Arcane Trickster / Fighter - +1 BAB d10 HD 4+Int SP
18: Arcane Trickster / Cleric - +1 BAB +1 Fort, Ref, Will d8 HD 4+Int SP
19: Arcane Trickster / Cleric - +1 BAB d8 HD 4+Int SP
20: Arcane Trickster / Cleric - +1 BAB +1 Fort, Ref, Will d8 HD 4+Int SP
Here's an example, why they warn specifically about using PrC like Mystic Theurge in combination with the Gestalt rules (not entirely sure, if the saves are done right, tho).
Damage Control: Talk with the player (and tell him/her that you did not know about these restrictions (1) only one PrC per Gestalt level, 2) no "fix multiclassing" PrC - both are in the rules, tho)) and let him/her remake the character.
Bye
Thanee