Can Bitcoin be "shutdown" if energy consumption for mining is heavily regulated?
Those questions have been answered multiple times.

The difficulty depends on the mining power. If there is a regulation and 60% of the miners are away, the difficulty would decrease drasticly within 2 weeks and the other 40% would need less power to mines the blocks. So the mining would not be hampered for a long time.


  Would BTC survive with only minor mining going on?


yes. Only a few people could still mine. The bitcoin network does not really need big mining-pool companies for that.

And you third question is a primarily opinion-based.