Pets, Henchmen,Tags, and Blue dots...

I love the game so far, but it seems poorly documented (or perhaps my search fu is weak) - here are just a few questions I have so far:

Pets: How to get rid of/change? What sets pet's initial level? If I get a new one, does it start with my level?

Henchmen: Why are they not my level when I hire them, and what determines their level?

Player tags: Why do players have their class/level info above their heads in some areas but not others? Why are some players noted in light blue and some in dark blue?

Guilds: How can I find out about a guild - number of members, etc? Any central registry?

To get rid of a pet, you have to find a "Tamer" to take it off your hands. In Pre-Searing there's one out by the guy that gives you the quest to tame a Stalker.

In Post-Searing, there's one right outside of Ascalon City.

A new pet starts at whatever level it is when you tame it (you can see this when you target it to tame it). They seem to 'catch up' to you pretty quickly though.

Henchmen levels seem to be related to the area that you hire them in, and nothing else.

Question 3 I dunno about the first part. I *think* Dark Blue means they're in a party, Light Blue means currently solo.

There's a section of this forum devoted to Guilds, but I don't know of a central registry per se.