Rogue-only? Why rogue-only? Anyone with a decent(14) intelligence score can lay claim to the DB, and absolutely anyone can lay claim to the 30% better HB crossbow.. Once you get to killing a white dragons, write here and I'll spoil you if you want. For what it's worth, the crossbows I'm talking about take care of that littel problem of yours
First, third and fourth chars might be forced to make some compromise, as in the begining, the 1st and 3rd use light armors, untill you gain bard spells, which can't be cast while wearing armors. So the 3rd guy switches to robes, and shares robes with the fourth guy. Since there are a few good robes in the game, I suggest you get the 4th, the wizard into light armors, the bard into robes and the fighter into medium armors and transfer 6 of his dexterity into str and con. Don't bother making him a wizard, as he'll be too busy tanking to cast spells..