I'm definitely interested to find out how she will do without guidance. But, she was pretty self-sufficient this whole season and I think that was the point of showing us that. Her "sister" has even less social skills than she does. :-)

The Omega symbol is the symbol of Darkseid, so I don't think those were Thanagarians, I think they may have been parademons.

From what I'd heard, the cancellation was due to bureaucratic financial issues with the contract DC had made with the state of North Carolina, where it was filmed. It seems NC reneged on their agreement to foot the bill for 1/2 of the production costs. So, since DC ended up paying the lion's share for this pretty expensive show when they were planning on paying for half of it, they cancelled it. I'd guess they'd have to find another state to film in (that would agree to the price of it) and I don't know if they tried and couldn't find others or they didn't bother because that would be even more money to build more sets and find locations elsewhere.