El dealio: Lerk spore & umbra only work if fired at alien or marine players & creates the area-affect thingy around them for 6-8 seconds. Either drains lerk's energy by 75%. The whole "shoot at spot and hope people stay in it" thing works with spore, but umbra's a little more tricky imo.
Magnetics = semi-counter spawn spam / secret weapon thing. Not sure what alien class it's for, but it causes targeted marine's gun & pistol to fly toward the alien & no pickup for 2-3 secs after the weapons hit the ground. Also has the reverse effect for nades - they fly backwards (passive for nades, or always in effect).
(you may experiance cancer in the next 5 minutes from reading this, so start thinking about what you would have done if you had a future beond 5 minutes.)