That looks very good. Now you just have to tell us where we can get the app :-)

The react-native-keychain package seems to be very well developed. This is also a requirement for using your app actively for voting and writing as well.

You wrote that you use the SDS API from steemchiller. Currently, I only know that it can be used to retrieve data from the chain, but not for transactions on the chain (e.g. voting). For this, as far as I know, you would have to switch back to the Steemit API (or an alternative RPC), so that the use is not independent if Steemit is unavailable.