You only need to claim your account once on the DTube Chain, it will remain yours. However when we launch the token out of beta, you will have your DTube account reset
Yes with the @dtube DTube account and the @dtube Steem account
We don't prefer anything in particular, it's the user choice. IPFS enables decentralized and censorship resistant hosting while an third party platform could bring you advertising rewards
4.No, we only curate original content, not shares
@dtube DTube account and the 
RE: DTube 0.9: Doubling up your rewards