Just keep them watered nature will do the rest. If they flower this year when the flowers die off do not dead head them this will protect the new buds from frost during the winter the old flower heads will fall off in the following spring.
Yes that would be ok.Cut them off dont break them this can sometimes cause damage to the plant.
I have a limelight hydrangea and it is really low maintenance. I would just make sure it has enough water. I only prune it if it grows a little too big on the sides, but otherwise I leave it alone.
Thanks for your response