first id suggest
GTFO it will inform you when your standing in stuff that can kill you.
id also suggest
inline-aura this will alert you when the best time is to use certain abilities ie Counter Spell, Kick, Tranq shot etc.
For your Hunter ill suggest these
FaceShooter it will help you with your abilities by telling you what to use and when
KHunterTimers use this to keep a eye on your trap timers and other things.
For your rogue you can use this to make opening lock-boxes a bit easier
Molinari also works for prospecting, disenchanting and milling.
For your mage at its level there isnt really much you need to worry about except sheeping.
Sheep Monitor will help with that.
to help with your network issues give
LeatrixLatencyFix a whirl it did wonders for me (from 500-600ms to 300-400)