All good questions, all of which are answered in the white paper. An "elected leader" is essentially the same thing as a miner that mines a block in Bitcoin. Miners can mine empty blocks in Bitcoin. This is OK, as others will step in for such defunct miners. Likewise, in Bitcoin-NG, another miner will step up if the elected leader does not mint microblocks.
Keep in mind also that NG would be layered on top of Bitcoin, so everything that works in Bitcoin will work in NG as well.
Keep in mind also that NG would be layered on top of Bitcoin, so everything that works in Bitcoin will work in NG as well.