How does Dero's use of uncles differ from Ethereum's use of uncles?
Does Ethereum also thwart 51% attack?
I forwarded your questions to the dev on Discord, but I can answer the second one: currently, Ethereum is *not* resistant to a 51% attack. That said, it is all but immune to one given the massive amount of hashrate it would require, and Vitalik it working on a new consensus algo that would require 99% of the nodes to be compromised (which sounds suspiciously like what Dero has already...).