1.There isn't a way to compare items side by side yet but I do believe the devs posted something about it being in the works iirc
2. You're pretty much dealing with the map the best way you can, just try to remember areas and locations
3. A linkshell is a chat channel for anyone currently part of it, sorta like a free company but just chat.
4. There is no voice chat that is part of the game but you can use an USB keyboard for easier typing. If voice chat is a concern, there's always teamspeak, mumble, raidcall, vent