Bran states: the children of the forest will help him(Benjen), when Bran learns that his uncle is missing He is scolded for bringing up Old Nan's stories.
Bran sees a child of the forest she is helping Coldhands. When he first speaks with the child of the forest, he feels as if he has slipped into one of Old Nan's stories.
Benjen taught Bran all the forts on the wall. He mentioned that Bran knew them so well he could be first ranger. Later, Bran knows about the Nightfort's ice stairs but is not sure if Benjen or Luwin told him. Bran did know that Benjen told him the ice was too treacherous for stairs.
Coldhands has uncommon knowledge of the nightfort (location and operation of the black gate)
Bran comments that Benjen is first ranger and might know where the 3 eyed crow is.
Coldhands is a ranger that knows where the 3 eyed crow is.
Benjen is described "as gaunt as a mountain crag"
Bran describes coldhands as "thin and gaunt"
CH covers the lower part of his face.
CH wears mottled blacks and grays.
Benjen was with the NW for 15 years
CH appears to have control over animals
Starks are known to be wargs
Benjen had blue eyes
CH has black eyes.
(eye color change is part of becoming a wight)
CH is recently deceased?
Clothing does not appear to be ancient and CH did not pick up new clothing from the traitors at Crasters.
(BR's blacks are all but rotted away in a couple of hundred years (give or take). Yoren's were worn to gray in about 30 (give or take). CH seems to fit between them.
CH surprised by wights under the snow. He was concerned when he reached the cave but continued on when he did not see the wights.
CH explains what happens to the body soon after death but not the long term effects.
Things to cast doubt on Coldhand's age
Some (ravens) would fly to the ranger and mutter to him. It seemed to Bran that he understood their quorks and squaks. The time when men understood ravens has been forgotten by man.
When Coldhands slaughtered the elk he spoke a tongue bran did not understand.
Leaf said No. They killed him long ago
If CH is a warg his ability to communicate with the ravens need not be ancient.
The Old Tongue is the language is currently in use by the Wildings and known by some NW brothers. Bran does not speak the old tongue as Leaf learned the common tongue for him.
The statement was made in as a correction to Bran's concern that the wights were going to kill CH if they leave him outside the cave. The statement includes that Leaf knew about the death of person now known as CH's. Bran's concern includes that he did not. Leaf knew both CH backstory and that CH did not tell Bran.
CH is not BR's meat puppet.
If BR warged CH, the elk, and the ravens, then ravens communicating with CH would be BR talking to himself. The elk was not as obedient when CH was not close.
BR knew about the wights under the snow outside the cave. CH did not.
Finally, Bejen's mission in the lands of always winter has either taken place completely off page or Benjen is CH. If Benjen turns up in winds of winter with a weapon or information that will defeat the Others, all that Jon, Bran, and Stannis did was simply a diversion. If Bran and CH's do the same thing the battle against the others is at least decided in the text.