Yea, the first theory (China) seems to have various supporters. I still think the speculation on the Halving event has a stronger effect on the actual price increase.
Your second statement is right. Bitcoin is coming out of a little "depression" because of the XT/Core/Classic flamewar. That helps the price to increase, and that's also the reason why I think that we'll never see $300 again (at least in the next years).
But I don't agree at all with your third statement. I'm not an Ethereum supporter (nor do I have some), but from 2013 on, there was never an altcoin that had more than 10% of Bitcoin's market cap (MAYBE Litecoin for a few hours on November 28, 2013) until the actual Ethereum hype. Even if that may be a temporary bubble, it's easy to see on CMC that altcoins' importance is growing.
However, Bitcoin will continue to lead the field at least one, two years more. Then I cannot guarantee for nothing