Food is an artifact type. Even though it appears on some creatures, it's never a creature type.

You can't sacrifice a Food to pay multiple costs. For example, you can't sacrifice a Food token to activate its own ability and also to activate Maraleaf Rider's ability.

Whatever you do, don't eat the delicious cards.

It doesn't matter what happened to the spells after you cast them. They each may have resolved, been countered, failed to resolve for some other reason, or another player may have gained control of them. As long as you cast a creature spell and a noncreature spell that turn, the ability will trigger.

If an effect replaces the number or type of tokens you would create, it applies to each of these tokens individually. For example, if you control Fae Offering and Academy Manufactor, you will create three of each type when the triggered ability resolves.

Creating a Clue token this way isn't the same thing as investigating. Notably, an ability that triggers whenever you investigate won't trigger because Fae Offering's ability created a Clue token.