I can answer the second question : you can claim the coins if you have at least 5 ETN.
For the first question, if I believe what I read, mobile mining is not far from airdropping, but I don't know much more. Not far from faucets finally, huh ?

I think ETN dump is due to the low amount mined in the first hours. If mobile mining gives good results, then it should go up again. I hope.