Yu-gi-oh questions please help

Question

With Silva and Gold of Dark World their effect says its special summoned if its discarded, but do they still get special summoned if your opponent used a card to discard them?

Also, with Type Zero Magic Crusher can you discard more than 1 card from your hand to inflict more damage? (Say i discarded 3 Spells from my hand when its active, does my opponent lose 1500 or am i only allowed to discard 1 each turn?)

Answer 1

Yes even if your opponent uses a card to discard it you can still speacial summon it.

Yes as long as you have 3 magic cards in your hand you can discard 3 you can discard as many as you like.  

Answer 2

if ur opponent gets rid of them, u can still summon them

Type Zero lets u discard as many magics as u want (u can send 2 to deal 1000 dmg or 12 to deal 6000 if u have the cards)

Answer 3

for gold and Silva, u get to summon them if either of u play card with an effect that discard them.

and for the Type Zero Magic Crusher, u can discard more than 1. it says "for each Magic card that you discard"