So, you want a sneaky Fighter.
Does this mean Hide/Move Silently etc skills, or Rogue class abilities, or what?
If you want stealth skills with the Fighter's combat ability, I'd suggest Ranger.
If you want full BAB & sneaky flavor, consider Justicar (C. War p.74), Consecrated Harrier (C. Div p.28)
If you want a lot of the Fighter's Feats but also want some versatility in abilities, consider Psychic Warrior with a very intentional selection of powers.
...Could you be more specific about what you want each of these 2 characters to do?