When a prophet was making a prophecy (e.g. Isaiah 55:1, the invitation) did it have a solution or an answer for the listeners (Israel) at that time, or did they have to look at it only as something in the future?
That would depend on what the prophecy was about. Some prophecies had immediate application, such as Ezekiel's prophecy against the sins of Israel in Ezekiel 20. Other prophecies had future application, such as Isaiah's prophecy regarding Cyrus freeing Israel from captivity (Isaiah 44:28-45:4). Some were so remote or so obscure that the prophet at the time did not fully understand the message he was delivering. "As to this salvation, the prophets who prophesied of the grace that would come to you made careful searches and inquiries, seeking to know what person or time the Spirit of Christ within them was indicating as He predicted the sufferings of Christ and the glories to follow. It was revealed to them that they were not serving themselves, but you, in these things which now have been announced to you through those who preached the gospel to you by the Holy Spirit sent from heaven --things into which angels long to look" (I Peter 1:10-12).
Some prophecies had an immediate application that also served as a future prophecy. For example, in talking about Israel's rebellious nature being like a teenager, God refers to Israel's youth, when He called them out of Egypt (Hosea 11:1ff); yet, this same statement is quoted as a prophecy regarding the Son of God (Matthew 2:15). Another case is where David talked about how people turned against him, "Even my own familiar friend in whom I trusted, who ate my bread, has lifted up his heel against me" (Psalms 41:9). Jesus refers to this passage and applies it to Judas. "I do not speak concerning all of you. I know whom I have chosen; but that the Scripture may be fulfilled, 'He who eats bread with Me has lifted up his heel against Me'" (John 13:18). But notice that Jesus did not quote the entire statement. He left out "in whom I trusted" because Jesus knew Judas' nature and never trusted him.
In movies, a hidden reference to something else, such as another movie, that is in plain sight but not noticed is called an "Easter egg." Easter eggs are used to prove who created the movie and to prevent copying. Modern movies did not come up with the concept. God has used hidden references to the future, especially references to the Messiah, that are clearly there when pointed out, but without knowing the fulfillment you would miss that it even was a prophecy about the Messiah. God used these to prevent people from creating a forced fulfillment of a prophecy -- you can't make something happen that you were not aware was supposed to happen. They also serve as proof that the prophecies and their fulfillment came from God.
Or a more literary way to look at this is that the Bible is filled with subtle foreshadowing of future events that gives coherency to overall story of the Bible, such as the similarities between the offering of Isaac to the death of Christ. Some prophecies also contain foreshadows.
Therefore, all prophecies cannot be lumped into one category or another. Some were designed to have multiple uses.