I am German, currently in the US with a B-2 visa (multiple-entry) for volunteering. The visa issued by the Embassy expires December 24th, 2015 (June 29th, 2015 - December 24th, 2015). When I entered the US end of July 2015, I got the stamp, saying admitted until January 26th, 2016.
For a family emergency I had to go back home for a couple of weeks. I re-entered the US on October 22nd, 2015 and the new stamp says admitted until April 21, 2016, as says my I-94.
So, if I don't leave the US, I can stay until April 21, 2016 without having an overstay, correct?
I have to visit my family for Christmas and would like to come back in January 2016, would this be possible?
What is the relevant date, the one on the issued visa or the one in the recent I-94?
Or should I leave and come back before December 24th, 2015?
I already have an existing ESTA which I used for entering the US in 2014. If I could not re-enter the US with my B-2 visa after December 24th, could I enter the US with my approved ESTA?
Is all this somehow affected by the fact that I take part in the green card lottery?
I just want to make sure, that everything is legal. As much as I like it here, I only want to stay here if this is approved.