1. The nodes in the network are not agreeing on the data set, they are agreeing on the expenditure of a resource
2. Due to #1 someone with enough resource can undo and rewrite history
In a true Byzantine fault tolerant system, the data set is append only and the rules used to determine the inclusion of new data rely totally on the existing data.
You are going to have trouble with your definitions of 'new' and 'existing' in a distributed p2p system. This is why we have POW in the first place, because the concept of time cannot be used to categorise these.
eMunie meets the requirements of a truly Byzantine fault tolerant system. It is append only, and history can absolutely NOT be changed. Historical data is considered in conflict resolution, and is also used to determine who (among other things) is eligible in the future to vote on which data set is valid in conflict situations.
I highly doubt this is true. I'd love to hear how you think you've solved it.