1.- Meera and He calls it thing

When meera try to blank a "he call it.." that its attached to a character, can blanked it and its discarded? i believe not because the text of attachment of he calls its a gained text not a printed text.

2.- Reek.

if i win a INT challenge with reek and for an effect die after claim, can i use its response to change reek for another opponents character?

3.-Coldhands.

If my opponent don´t have any character to "freeze" with coldhands, Can i use him in my own characters only? im not sure because the text said choose one and..

4.- Abandoned Fort

Recently i saw a reprinted version in English of abandoned fort in english that said that affects "attacking and defending house bolton characters" , this it´s true? now affects both?

1.- Meera and He calls it thing

When meera try to blank a "he call it.." that its attached to a character, can blanked it and its discarded? i believe not because the text of attachment of he calls its a gained text not a printed text.

You are correct that the "Attached character gets +2 STR" text is gained text, so blanking the card has no effect. Also, once the event is attached, it turns into an attachment as its only card type. Blanking it could not discard it, even if its attachment text was not gained text.

2.- Reek.

if i win a INT challenge with reek and for an effect die after claim, can i use its response to change reek for another opponents character?

I'm not sure what you mean by "die after claim"? Do you mean the opponent uses something like "A Lannister Pays His Debts" to kill Reek before he can use his ability? In any event, yes: You can use Reek's Response while he is moribund.

3.-Coldhands.

If my opponent don´t have any character to "freeze" with coldhands, Can i use him in my own characters only? im not sure because the text said choose one and..

The "if able" in Coldhands' text indicates that he can be used even if some players do not have characters to choose. His effect will work on whatever characters are chosen.

4.- Abandoned Fort

Recently i saw a reprinted version in English of abandoned fort in english that said that affects "attacking and defending house bolton characters" , this it´s true? now affects both?

I haven't seen a reprinted version, but the general ruling from FFG as I understood it was always "play what your card says." It wouldn't surprise me if they updated the English language version to match what the non-English versions say.

On #4: are you sure the version with "attacking or defending" is the most recent one? It would surprise me that FFG would make an update in a reprint without putting it in the FAQ first.

Abandoned Fort has an 'attacking or defending' card image on OCTGN, which must have originated from somewhere. That said, I have never seen a physical card with that printing, so my suspicion is that it's an old testing leak or something that has made its way into databases.

Play what your physical card says (although I realize that in some localization efforts, that can be difficult).

The French version cards have that wording. Which means it was the wording FFG sent Edge (and probably other editors) for translation. But when the chapter pack came out, the text had changed to "attacking" only. Given the card has not received an erratum since it came out several years ago, I'm inclined to think the wording is meant to be "attacking" only.

All non-English versions say "attacking or defending," all English versions (unless a reprint says otherwise, but Khudzlin is correct that they usually highlight reprints with new text in the FAQ) say "attacking." This has always been true. For years. Because FFG has never tried to issue errata that makes the various versions match, the rule has always been "play what you have" - unless there is a local rule, of course.

Of course, if the English version of the card is the official version for rules disputes at your event (like the World Championship Event FFG holds in Minnesota), that answers the question, too.