And what does it mean returning to 3 minute blocks, i thought now it is 3 minutes blocks, isn't it?
Well you're touching upon a not exactly bright chapter in UNO's history. The previous dev team - which turned out to be more or less Wolong's crew - made some modifications to UNO, those resulted in faster block times. Bryce and Blazr are now restoring UNO to the way it was originally created and meant to be.
I will leave the specifics of your other network related questions to people that actually know that stuff.