Powering LCD from an Arduino pin

I would think it's ok. One thing you should consider though, is the voltage sag when a load is applied to a digital pin. As far as I know, they are only guaranteed to output 5V without an appreciable load. 17ma might cause it to drop somewhat (perfectly normal and within specs), and this might be below the minimum supply for the lcd module to function properly.

I don't think it would hurt to try though.