The "Ice" attachment for example.
Could it be used to kill the Red Viper who is immune to character abilities and events?
Semantically it could be argued that it is an attachment ability and not a character ability, but my group is also new to the game so we are just trying to understand what means what.
Thank you in advance!
It's as you say. Ice is an attachment, not a character, so it's effect is not a character ability, and TRV is not immune against it. To be immune, he would have to be "immune to triggered abilities" (like KL Joff) or "immune to opponent's card effects" (like Cat o' the Canals). You know what the differences are between the two?
P.S. "Immune to attachment abilities" would work too, but no card in the card pool currently has that as far as I'm aware.
Thank you for the response!
I think I can deduct the difference between those two.
Triggered abilities being response type effects only and opponent's card effects are basically broadening the immunity to any card the opponent has that can affect characters.
I could be wrong, but opponent card effects would be inclusive of character abilities and triggered abilities(along with anything else written on a card played by the opponent that could normally affect characters).
Yeah, almost. 
"Card efffects" is the broadest possible category. It includes any effects that are governed by text on cards, including keywords. "Opponent's card effects" are, well, effects on cards controlled by your opponent (Who woulda thought, right?).
"Character abilities" are effects on character cards (not effects that affect characters!) excluding keywords.
"Triggered effects" are all effects on cards that are preceded by boldphased Response: or Phase: text.
So, you see, it's all basic set theory: Some effects are Character abilities, but not Triggered effects. Some are Triggered effects, but not Character abilities. Some are both. Some are neither.
If you'd like to read up on this stuff, it's all from the FAQs, page 8. If you've got further questions, don't hesitate to ask.
Ratatoskr said:
It's as you say. Ice is an attachment, not a character, so it's effect is not a character ability, and TRV is not immune against it. To be immune, he would have to be "immune to triggered abilities" (like KL Joff) or "immune to opponent's card effects" (like Cat o' the Canals). You know what the differences are between the two?
P.S. "Immune to attachment abilities" would work too, but no card in the card pool currently has that as far as I'm aware.
Leyton Hightower makes your Maesters immune to opponents' attachments and events.
Ratatoskr said:
If an attachment or some other card says "Attached character gains 'some amount of text...'." then the "some amount of text" would be considered a character ability. The example that comes to mind is Lost Oasis, which says that the character gains "after this character bypasses a character by using Stealth, kneel that character." Because the text is "gained," the kneeling is considered a character ability, not a location ability. So a character that is immune to character abilities would not be knelt when it was bypassed.
Thank you all for the replies. I was unaware that character abilities did not include keywords until just now. That is very important for how valuable that immunity is to my group now.