If the Galaxy handset has been unlocked - yes.
the phone should come with a sim card which is to a specific network, if you don't have a sim card you can go to a phone shop and buy one. It should be about $5 or £3 for one.
You can use the same SIM card for your iPhone 6 that you used in your iPhone 5.
Provided the new handset is unlocked... yes you can.
Yes
5-10 usd
You just wait about 5 Sim hours and they will come back!
Assuming the SIM card is the correct size for the iPhone (ie not a micro SIM) - there's no reason why not. Since you say it's unlocked - it should accept any networks SIM card.
Yes the iphone 4 uses whats called a micro sim card it is smaller then the regular sim card out there. At www. phonetraderonline.com they can custom cut your existing sim card or provide you with a micro sim for your carrier.
The Samsung Galaxy Note 5 as of this writing is not out yet. It is in development.
Cook for 5 seconds in a microwave oven, this will do the trick.
No you cant only in telstra