1. It only means, the distance you teleport must be a multiple of 5, so you can't teleport 7 feet, for instance. Basically that just says you can't use it to teleport to a location that's not a standatd-square (which is always a 5 ft square). You can teleport any distance per step as long as you don't go over your daily maximum distance. So yes, you can teleport over a Pit. As for fog of walls, I'd say no, because SLAs work like spells, so unless otherwise noted you need line of sight and line of effect to use them.
2. Not clear from the description but since almost all other forms of teleportation require a touch to bring someone along, it's probably save to say yes.
3. No, SLAs don't have any components, so you can use Dimensional Steps when you are silenced and in shackles. Note that you must still concentrate on them and still provoke AoOs when you use them. This probably means that using Dimensional Steps requires defensive casting when used, since it's just the movement (i.e. the teleportation) itself that doesn't provoce, while the "casting" of the SLA still provokes.
A few questions about Dimensional Steps;
1. What does the 5 foot increments mean? Can i step over a 15 foot pit, through a wall or a stinking cloud?
2. Do i need to be physically touching other characters to bring them with me?How do i do this in combat?
3. Does a spell like ability have a verbal or somatic component?Cheers
1. It means the distance you teleport must be a multiple of 5 (i.e. you can't teleport exactly 47 feet, only 45 or 50).
3.
A spell-like ability has no verbal, somatic, or material component, nor does it require a focus.
As for fog of walls, I'd say no, because SLAs work like spells, so unless otherwise noted you need line of sight and line of effect to use them.
I'd disagree here. Not all spells require line of sight and line of effect. Some spells clearly would not work at all if they required LoS and LoE (e.g. Plane Shift) Others require just one or the other. Read the section under "Aiming a Spell" to see the differences. For example, you need Line of Effect for a fireball, but not necessarily Line of Sight; you could be in complete darkness with no sight at all and still fire off a fireball by designating that you are trying to center it 40 feet straight ahead (whether you can get it 40 feet straight ahead or not depends on the terrain and what not).
Likewise, the teleportation spells would have substantially reduced effects if LoS and LoE are required. No teleporting to anywhere you can't see...which would vastly limit the range of teleport and greater teleport. And no teleporting out of dungeons or from under ground or inside a building, since LoE would be blocked. This is counter to how the spells have traditinoally been used for a long long time, and also to how they are described in the books.
So basically, yes, you can use dimensional steps to teleport out of a fog or to the other side of a wall. And you can bring others with you so long as all teleported creatures are touching (although it uses up more of your teporting distance for that day for each creature teleported).
Generally, I'd treat the dimensional steps ability as a Dimension Door spell but with greatly reduced range and without the limitation of not being able to take any further actions. There does not appear to be any possibility of being off-target, although you could potentially teleport into a solid object (thus taking damage and being shunted to the nearest open space).
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Spell like abilities require no verbal, somatic, or material components. You can use the dimensional steps ability while completely naked and bound and gagged, or even grappled. You can do it with your hands full or while wearing armor. You still provoke Attacks of Opportunity for using a SLA, and you may need to make appropriate concentration checks as if casting a spell (i.e. you can cast defensively, or you are subject to violent motion, or are being grappled).
I agree with most everything said except the LOS question. Most spells require LOS for obvious reasons. I haven't read the description lately, but it makes sense that teleportation only requires that you know where you're going. Such as Ten feet left to get through this wall. However teleportation comes with risk. If you're wrong and that wall isn't thin enough for you to get through with a ten foot jump you take damage and are shunted out to the nearest available space. I believe the damage is something like 1d6 per five feet, but don't quote me on that. Additionally when you teleport without LOS you have no idea what the space looks like. The room on the other side of the wall could be full of enemies, oozes, a pit trap, acid, an angry dragon, etc.
Teleporting with LOS is obviously MUCH safer.