Hook up the other end of the strip data to the arduino. It looks like you got it right, but some times looks are deceiving a and it won't hurt to try
I think it could hurt. The OP would be connecting an output to an output, causing damage to either or both. A resistor, e.g. 330R, between the Arduino pin and the data line should protect against this damage.
@wdwocnj, you should have a resistor between the Arduino pin and the first pixel. Anything from 100R to 1K should be ok, ideally 220R or 330R. You should also have a large cap, e.g. 1000uF across the power wires to the LEDs.