You may have a total of 15 fusion and synchro monsters in your extra deck(renamed from fusion deck with the addition of synchro monsters)
Destroyed or tributed Fusion Monsters go to the graveyard. They will return to the Extra Deck if something tries to return them to hand or deck.
Yes, but you have to have the fusion elements.
Just like regular monsters, Fusion monsters will go to the Graveyard if they are destoyed. If a Fusion monster is supposed to "return to the owner's hand" or "return to the owner's deck" because of a card effect, it is returned to the Extra/ Fusion Deck.
yes it does fusion but i don't think it has fusion monsters
A Fusion Summon, or the Summoning of any Monster (Synchro or Fusion) from the Fusion Deck (Extra Deck) is a special summon and so Trap Hole will not work on it.
It is currently now called the "Extra Deck", and a maximum of 15 cards (Fusion, Synchro, Xyz Monsters) are allowed.
No, you cannot use Fusion Substitute Monsters for "Future Fusion". You can, however, use Fusion Substitute Monsters for "Chain Material" as long as those Fusion Substitute Monsters exist on your field or hand. The reason Fusion Substitute Monsters cannot be used from your deck is because they have no substitute ability while in the deck and thus cannot be used as replacements for other Fusion Material Monsters.
if you have the necessary cards (fusion materials) in your hand to fusion summon yes, since fusion monsters have their own deck area.
You cannot return fusion monsters to the hand. Fusion and synchro monsters have to be returned to the extra deck.
No. If a card says to 'search your Deck', or 'send a card from the top of your Deck', this means your main deck. If something tries to return a Fusion monster 'to deck' though, that will put it back in your Extra Deck. That doesn't mean Extra Deck is the considered the same thing, that's just where Fusions and Synchros go when something tries to put them back in Deck.
Honestly, it depends on what type of deck you use. If it's the Cyber Dragon deck, you can use the spell cards "Polymerization", "Super Polymerization", "Power Bond", & "Instant Fusion". But it mainly depends on the type of deck you use.