Is it possible to have supernode and use delegate harvesting at the same time on one wallet?
Good question

A supernode is just a node with minimum requirement. It has nothing to do with a wallet. You can of course harvest with the delegated account that the supernode is using.
Xem Nem 2017/2018
1/10$ I pray for this

10$ is pretty impossible even in 2020......i wish it happens though

I think XEM can easily reach 1$ sooner than later. But it really doesn't matter when or how it will reach that what matters is that is will really gain true value in terms of foundation to reach 1$. I expect NEM development will be boosted from now on way much faster than the past years. More Devs will be involved, more features, APIs, side chains, ..... Bottom line NEM already has strong community and technology, the real growth will be based on how NEM community and technology will expand and advance within the coming months.