use static command

yes

2) When you are following a player can not teleport to "spawn" (example)

3) when you vanish you put the night vision

I'm sorry for my English, but I'm using google translator

My opinion this idea is completely unnecessary.

What good is saving the ip of a player?

I do not think you could do something like ;)

http://staffplus.userecho.com/topics/41-invis/

No, I can not hope to do another update.

is sound-names

nope, its default ;)

https://gyazo.com/c1d229fa4ccd76fa9b0f1c19fb8b26a3 (Folder Plugins/Staffplus/Config)