No, you can only use you're monsters for Scrolls Of The Six Samurai. You can never tribute something you don't control.
A Tribute must be a monster you control, unless specifically stated on the card. Cards like Soul Exchange, and Chimeratech Fortress Dragon, specifically let you use an opponent's monster. But Malicious Edge does not say so, so normal tribute rules apply.
Clearing up some possible confusion - Soul Exchange doesn't 'take' monsters, nor does it do anything to them on resolution, except for set up a condition that says you can tribute it as if it was one of your own. You tribute it therefore in exactly the same way as if it were on your side of the field. There is nothing stopping you tributing it, and a monster on your side of the field, to summon a Lv7 or higher monster. In fact if you used 2 Soul Exchanges, you could summon a Lv7+ monster with both of them.
A Level 8 monster needs two tributes, so you can tribute a Lv5 monster, but must also tribute a second monster too.
A level 7 monster needs two tributes, so you can tribute a level 6 monster but must also tribute a second monster.
Because the protected Six Samurai is not being destroyed by Torrential Tribute's resolution, then it can be used to save one of the Six Samurai that is being destroyed.
Yes you can, Soul Exchange simply offers a monster on your opponents side of the field as a tribute, as well as any others you may control.
Yes, you can activate Torrential Tribute whenever a monster is summoned. Here's a hint you can also activate on your turn to destroy your opponents monsters.
No, you do not 'tribute' the Synchro Material for a Synchro Summon. They are sent to the graveyard, not tributed. You can tribute an opponents synchro monster for "Assault Mode Activate!" to summon the assault mode monster from your deck.
No, there's absolutely nothing of the sort. The monster goes to the graveyard, just like any other tributed monster.
Tribute a WIND, EARTH, FIRE and WATER monster. destroy all cards your opponents controls
A Tribute must be a monster you control, unless specifically stated on the card. Cards like Soul Exchange, and Chimeratech Fortress Dragon, specifically let you use an opponent's monster. But Malicious Edge does not say so, so normal tribute rules apply.
Clearing up some possible confusion - Soul Exchange doesn't 'take' monsters, nor does it do anything to them on resolution, except for set up a condition that says you can tribute it as if it was one of your own. You tribute it therefore in exactly the same way as if it were on your side of the field. There is nothing stopping you tributing it, and a monster on your side of the field, to summon a Lv7 or higher monster. In fact if you used 2 Soul Exchanges, you could summon a Lv7+ monster with both of them.
You can tribute a special summoned monster, yes.
A level 7 monster needs two tributes; you can tribute a level 5 monster but must also tribute a second monster.
A Level 8 monster needs two tributes, so you can tribute a Lv5 monster, but must also tribute a second monster too.
A level 7 monster needs two tributes, so you can tribute a level 6 monster but must also tribute a second monster.
A level 8 monster needs two tributes, so you can tribute a level 6 monster but must also tribute a second monster.