Thank you for questions...

• We have PIN code that encrypts your data/keys within app and working to get memo encryption working with our upcoming messaging/chat feature.
• For now, we are working to have full support for browsing Steem posts and use its full potential/features
• We have selection of server/node in both eSteem Mobile and eSteem Surfer apps, if you see connection is not working for some reason (server downtime) or IP blockage from government, you have ability to change server to any public or private or local ones. It keeps you connected to the network. Internal DNS is interesting concept and I am sure with technology maturing, we will be able to adopt it. Both eSteem apps are lightweight applications, because they connect to user selected server to fetch the data. But we are also exploring concept of light-weight stand-alone version, that would allow you to download compressed blockchain data locally and surf offline, we will see if it becomes reasonable or viable solution as you know size of blockchain is growing fast and custom lightweight apps would be perfect solution to surf years old posts.
• Thanks for invite, I am in steemspeak discord and will try to jump in later

Update

We have released transfer memo and comment encryption with 1.0.3 release, please have a look and let us know if it works for you. Thanks!