Yes. Generally speaking, the bigger the fly, the heavier the line needed. A #2 is a very big fly.
Leaders come in different lengths and different tippet sizes. For your fishing, I'd think there's really no reason to go with a leader longer than 9 ft.
Again, generally speaking, the tippet represents the terminal 20% of the leader. For some historical reason, which I think has something to do with making watches, the X system is used for tippets. The rule of 11 tells you the diameter of the tippet. 11 - 3 = 8 which is the diameter of a tippet in thousadns of an inch. A 5X tippet is .006" in diameter; a 2X tippet is .009" in diameter.
Another rule of thumb is the rule of 3. A flies size divided by 3 is the tippet size that should generally be used. So for fishing a size 6 fly, I'd generally start with a 2X leader. For size 4 or 2, I'd start with a 1X leader. This is just a general rule of thumb though...some flies are more bulky and or wind resistant than others, so it may be necessary to go up or down on tippet size.
By the way, the heavier the rod, the more fish it can handle as well. You could probably land a steelhead on a 5 weight. But you'd probably play it so long that the lactic acid build up would kill it. (This is my guess, I've never tried it on a 5 weight).