1) No.
Discarding an item is not condition. It is an mandatory action caused by the card, like the corruption check, that may ultimately not happen (if target diplomat is an ally).
Execution of the card forks in two directions:
failed cc - end of execution,
not failed cc - discarding of an item, dice-roll. That in turn forks in two directions (canceling the attack, non-madatory searching for resource, end of execution|end of execution).
In this aspect Token of Goodwill is similar to Rats!*. It is not known at declaration whether player will opt to discard an minor item, or to wound an unwonded character, but at least text of Rats! requires having some minor item. Text of Token of Goodwill does not.
Because it is not known at declaration which of directions will be taken, discarding of an item is not considerd declared at this point thus the item is not considered target, even if it is specified by number and type. So the item is not implicite condition of Token of Goodwill.
2) No.
For the same reason as above. If for any reason the target diplomat cannot make cc, the card is proceded further without problem. Tha same applies to inability of discarding of the appropriate item.
The card begs for errata.
E.g. changing "Playable on a diplomat whose company is facing an attack of the type listed below." to "Playable on a diplomat whose company is facing an attack of the type listed below and have an item of appropriate type."
Then a having of minion item of appropriate type would not satisfy condition of playing the card. Not only for FW player, but in general, because:
*) or to A Lie in Your Eyes.CRF, Rulngs by Term, MELE vs. METW wrote:Hero items may not be used as conditions for minion resources, and minion items
may not be used as conditions for hero resources. Note that a Fallen-wizard may play
special ring items regardless of the alignment of the gold ring item tested.