A test is a roll of the dice, so yes. See Rolls and Tests, Torchbearer, page 6.
It’s an Ob 0 test so it doesn’t count toward advancement. See Obstacle 0 Tests, page 104.
You may tap your nature on any raw ability or skill test. You can’t tap your nature for town ability tests (Resources and Circles). See Tapping Your Nature, page 110. Remember that unless the conflict falls within the nature of the character rolling for disposition, they will tax their nature by one if they tap it for the roll. e.g., if the party runs away from a threat, triggering a flee conflict, a human with the Running descriptor could tap their nature for the disposition roll without taxing it.
Use of wises and traits are also fine, as with any other uses of those, it must be accompanied by fitting description. If Gerald’s player wants to use his Kobolds-wise for an Of Course! when rolling for a kill conflict disposition, the player must say Of Course! and then explain how the action they described that set up the conflict almost led them into error, but then they rememered a thing about kobolds (which the player shares with everyone) that allows them to adjust.
The GM should work with the player to massage the new fact if it doesn’t make sense or is outlandish/ridiculous in the context of the world. Be flexible and help them use their wise if you can, but it’s OK to say ‘no, that doesn’t fly’.
For example, Bow-wise won’t benefit you just because you happen to be using a bow. You need to describe how your knowledge of bows gives you the advantage as you initiate the conflict. The GM and your fellow players should help you flesh out the idea until it’s plausible. But if the fight is taking place in tight corridors with lots of twists and turns where a bow is more hindrance than help, it’s OK to say the wise isn’t applicable in this situation.