dpkg -l | grep spice
ii spice-vdagent
0.10.1-1 Spice agent for Linux
spice-vdagent ?? Really? Why?
via man page it gives this link:
http://www.spice-space.org/documentation.html
It appears to be some kind of remote server or service. Why is it included?
Is it safe to remove or is it tied to Tails function?

Please not that Tails developers do not endorse rude behaviour. The answers to the original question are unecessarily harsh.
Although, please note that Tails resources are very, very limited. If you want to customize Tails, be ready to do your research. If no one (be it another Tails developer or other readers of the forum) answered your question yet, it might be because no one is actually interested in helping you. Sorry but there is users to support, bugs to fix and features to develop.
To answer your question about what
spice-vdagentis, please read more about it on http://spice-space.org/. We ship it for the same reason we ship the VirtualBox and the VMWare drivers: for happy use in virtualization software.This is the wrong way to do it. Tails is a live system. This means that if your goal is to remove what you do not understand, whatever you remove while the system is running will still accessible in the lower level of the union filesystem. If you want to properly remove packages from Tails, you need to learn how to build it.
Feel free to trust or distrust Tails and its developers.
Javascript is enabled by default because most Tails users don't even know what Javascript is. But they do know how to recognize a broken website. And then go back to their Windows system full of malware. If you want to target another userbase, Tails is free software, so feel free to fork.
Regarding the NoScript whitelist, again please research before making unecessary assumptions. ?This is something that will be fixed in the next release.