1. The difficulty of most traps won't exceed 40. If you want to recover them rather than disarm the traps, you should expect a DC of 50. Some traps are a little higher, but this should see you through most of them.
2. Rogues shouldn't have metal armour, period [img]tongue.gif[/img] The main reason is not stealth, but rather the fact that your dex bonus doesn't count while wearing armour, and the fact that they take you closer to your weight limit that you want (unless you've spent a lot on strength as you may well have with a fighter/rogue).
3. I'd think so too. And intelligence is double important as it also lets you pick more skills per level, allowing your rogue to have a broader arsenal of skills.
4. I used Linu. When sneaking, I told her to stay back and let me take care of things. She's a nice aid in combat, and, for me, essential in the tougher fights (harm spells, you know
).
By the way, I doubt you really need a fighter/rogue. My rogue started out using missile weapons only, grew to shortsword and shield (she was a halfling) and in the later stages could wield a longsword (doublehandedly) in combat and get away with it. They can look after themselves with a bit of training.