Codex: Space Marines... am I missing something?

Codex: Orks was filled with "huh?" moments. Are dakka-guns on bikes twin linked? What is the actual profile of a dakka gun? Can Stormboyz Waaagh? Can a mob of boyz with shootas have a Nobs with a power klaw, etc.

Codex: Space Marines is starting to cause me some head scratching. First up is the ubiquitous Signum, a sensor previously used by Techmarines to improve shooting of the squad to which they are attached. The rules for the Signum have been changed to prevent it from being used as "Gets Hot! Insurance." Instead of rolling misses (and 1's are misses!) it improves the ballistic skill of a squad member. Great! The only problem is that nobody can take one. The Techmarine doesn't have a signum in his wargear anymore and he can't buy one. In fact, no model that I can find has an option to take a signum now. Did I just miss it?
EDIT: Devastator squad sergeant gets a Signum by default now.

Next, the Razorback! First off, I love the option to have different weapon options than the heavy bolter/lascannon of the last edition. The one that I wonder about is the lascannon/plasma gun combo. In the roster entry, the upgrade specifies a single lascannon and a twin linked plasma gun. On the main page describing the Razorback a variant is described that includes a single lascannon and two twin linked plasma guns. Based on the Ork FAQ using the description page over the roster page I'm guessing it will end up as two twin linked plasma guns, so I'm going to delay modeling one of these until I know for sure. The twin linked assault cannon would use the same turret mount as a Land Raider twin linked assault cannon, but I don't know if the regular Land Raider box includes that particular bit or just the twin linked heavy bolter. The new plastic Crusader / Redeemer box has a twin linked assault cannon bit, but both variants use it. Any Land Raider owners out there want to help me out with this info?
EDIT: I completely misread this. It's "single lascannon and twin-linked plasma guns." One twin linked gun, just like it says in the army composition page.

Honor guard / Command Squad / Servitors: Both the Honor Guard and Command Squad have text that indicate that their inclusion does not take up an additional HQ slot. The servitor squad entry does not have similar text. Does that imply that servitors will take up an elite slot? I hope not. Also, am I missing something or do the independent characters no longer have to be attached to the squads they allow? Text seems to imply that the servitor squad can exist without the techmarine; there are even rules specifically based on the techmarine not being in the squad, and I'm guessing that's not just a "techmarine dies" rule.