by Dumon
Items, once built (turned over) generally stay that way. Until an event or adventure card says otherwise! So you can "use" the shovel repeatedly...I am absolutely sure that you could increase the weapons level by 4 if you place 4 pawns there. I am, however, not so sure if you could increase it multiple times with just one pawn (I'd say no) - would have to look that one up.
The dog is just a neutral action pawn. He is no figure, and actually needs nothing. the downside is that he cannot do anything alone, and cannot be used for all actions (if I remember correctly, he cannot build).
If you build the knife, you increase the weapon level instantly. That is why it is mentioned on the card. Whenever a +Weaponlevel is mentioned, you do that.
You cannot have strength 1+1(knife), because the minute you build the knife, you increase your weapon level (I guess that is what you mean by strenght, as the characters have none themselves). So you would actually have a WL of 2. If the animal you fight does 2 damage, then nothing happens in this case. The decrease comes afterwards. And if your WL is decreased by 2, then it is zero from then on. The knife only gives you its bonus once!
If you, however, happen to have a WL of 1, and a card that gives you TEMPORARY WLs (let's say 1), then the attack of 2 would do nothing (would not give you a wound) if you use the card. However, if you then have to decrease the WL by two, you can only do so by 1, as the temporary WLs are not counted. Which in turn means you would gain 1 wound.
Yes, and no. It depends on the discovery tokens (see description). However, as always, discovery tokens are not immediately available when you get them - they only become available AFTER the action phase!
Hope that helps.