can i charge my apple tv remote controller with my iphone 6 charger

Yes, that is one of the intended ways:

Charge your Siri Remote or Apple TV Remote - Apple Support

I do all the time. you will not see a progress bar but I leave mine charged for about 1/2 a hour and then check using the apple tv. it will take a few hours for a full charge, I think.

Yes, actually with any charger that fits.