Welcome to
VRHeads! Please join the site. Here's how....
http://forums.vrheads.com/ask-questi...eads-com-8087/
I'll try my best to answer what I can, PLUS I put out a call to others for more advanced help looking for someone who might actually own the device.
1. You do NOT need to buy the brand they recommend, just make sure you get a card that meets or exceeds the specs they require. Your local electronics or camera store will know.
2. Without the SD card then you can only use the Insta360 while it is attached to your phone and it will save directly to your phone. AND the videos will probably be VERY large. Get a card!
3. I don't know, hopefully a user will be able to answer this.
4. You need a cardboard app. Get Google Cardboard and Cardboard Camera
5. No clue
6. Here and also the 360 Camera sub forum at Android Central
here