Perhaps one of our Classical literature experts will reply to your specific questions. In general, seeking any real person behind a folk story is a fruitless and frustrating endeavor. This sorts of questions crop up frequently - in general and on this subreddit. I developed an answer for /r/askhistorians, which I used in an appendix for my Introduction to Folklore. Here is the answer I developed:

When I see the posts like this asking about whether there were real people or events behind legends, myths, and/or the ancient gods, I respond with a number of observations. First, the idea that the gods and heroes of legend are based on real people had an early proponent in the Greek, late-fourth-century BCE writer, Euhemerus, giving his name to this approach to myth and legend: Euhemerism. Folklorists generally regard the idea that there was an actual basis for most oral tradition as barking up the wrong tree, because the original “real” event behind a story is usually elusive and searching for that core is a futile exercise. In addition, research into how stories began usually concludes that they emerge in a rather spontaneous way, typically without an actual incident to inspire them.

A few examples: the Classical Greek story of Perseus is an early manifestation of a widespread folktale, catalogued by the twentieth-century folklorists Antti Aarne and Stith Thompson as AT 300, “The Dragon Slayer.” Was there a proto-Perseus who rescued a maiden from some sort of extraordinary threat or perhaps from some sort of human sacrifice? It is hard to answer that question, but it is not hard to imagine how far back in time that proto-incident would have had to occur: AT 300 is spread throughout Eurasia. It was collected from cultures that could have no conceivable literary connection with ancient Greece, and yet the shared assortment of motifs in the numerous variants clearly show some sort of genetic, that is, historically-connected relationship. Would we need, therefore, to go back thousands of years before the first recordation of the Perseus story in order to find this proto-Perseus? It is much easier to understand that the folktale simply diffused and that one of its manifestations was in ancient Greece.

Now, let’s consider another example that has inspired a lot of spilled ink. A simple Google search for the “origins of King Arthur” provides more websites than one could easily read in a week. Was there a proto-Arthur? Perhaps. Maybe there were several. But what does that prove? Every society has remarkable characters, and it may be a natural process for these sorts of individuals to attract all manner of traditional stories that have nothing to do with the original inspiration of the cycle of legends.

So what do we have with Arthur? Was there a core source (or sources) for this legendary character? Let’s concede for the sake of argument that the answer is yes. Now, did this individual have a great warrior at his side who became ensnared by the leader’s wife in the fashion of Lancelot and Guinevere? That is more problematic since this type of story is also associated with Diarmuid and Grainne in the Irish court of King Finn and with the Cornish stories of Tristan and Isolde in the court of King Mark. One could even argue that it is the story behind Helen of Troy. In fact, it appears that this was a widespread type of story that became associated with various courts of historical legend. We cannot conclude that every great king had a queen who was attracted to one of his warriors and coerced him to take her away. This is simply a story that was attached to cycles involving great courts. In short, the further one goes back to find the “real Arthur,” the less the candidate (or candidates) look like the King Arthur who has been beloved for centuries. The proto Arthurs are not really King Arthur. They may be seeds but they look nothing like the tree that would grow over the centuries. We do not hold an acorn and say “Ah, I have in my hand a mighty oak tree.” It is not yet a tree. It is a seed. And the two look very different even if they are genetically linked.

One more example: there is a widespread legend told by countless families of the ghostly appearance of a loved one in anticipation of news that the individual died. This became a popular tradition in post-Famine Ireland because so many relatives lived in North America or elsewhere. But it is frequently told by all sorts of people internationally. So we can ask, are there real-life, actual inspirations for this legend? That is, do the spirits of the dead actually come to visit loved ones? Well, how the hell should I know? To paraphrase a famous line from the television show “Star Trek,” “Damn it Jim, I’m a folklorist, not a ghost hunter.” And I have no intention of becoming a ghost hunter. It doesn’t matter what is behind stories so much as it does that people tell these stories. I’m in it for that part of the game; I consider stories as they are told over time, to gain from that material some insight into the past, into culture, and into the human condition. I am a folklorist. And with that, my plate is full.

Oh, I love this question. Most of my answer is taken from the series of lecture given by Denys Page called "history and the Homeric Iliad".

Short answer we have very little hard evidence for the existence of any single person in the Iliad and Odyssey. However, we can make a lot of inferences and suppositions that strongly point to the existence of many of the people in the Iliad.

• Firstly, Priam and Troy. Most of the evidence here we get from Hittite documents, specifically the Manapa-Tarhunta letter. The story is that Manapa-Tarhunta was a Hittite client king who was overthrown by a guy called Piyama-Radu, which sounds a lot like Priam. There are also references to someone called Alaksandu. One of Priam's sons in the Iliad was called Paris-Alexander. Both were kings of a city called Wilusa, which comes into Greek as Ἴλιον (the letter for W (called a digamma) dropped out of the Greek alphabet very early on). This seems like very good evidence for the existence of a king Priam as king of Troy. His deeds however, were, in my opinion, a later construct of the epic poets.

• Secondly, Epithets. The point here is to prove that the epithets and the people they describe are incredibly ancient and point to the existence in about 1400 B.C of the people they describe. This is gonna get a bit technical, but there it is. In epic poetry people get epithets attached to their names. For example, Achilles is called "πόδας ὠκύς" (swift footed) Hector is called "kορυθαιολος" (bronze helmeted) and Ajax appears with a "σακος" (a type of large shield with a boss) with "ἑπταβοειον" (seven layers of oxhide). All three of these epithets are very ancient in origin and come into Greek nowhere else. They also appear only attached to the people with which they are associated. The shield of Ajax is the most interesting in this regard, it is very large and carried "like a tower" meant to be set down and defended. We have illustrations of shields like this from the late helladic era (around the time that the Trojan war was fought). Such shields then went out of fashion in about 1300 B.C in favour of round shields (ἀσπις). The Iliad preserves the memory of these ancient weapons and the people they were associated with. The shield is embedded in the verse with one person alone, Ajax and due to the ossified form that the poetry comes down to us it has likely been that way for hundreds of years before it was written down. Shields are mentioned hundreds of times yet Ajax is the only one with a tower like shield with seven oxhide layers. It therefore follows that there was at some point a guy called Ajax who had a particularly large shield who was transmitted down to us through oral poetry. It is also quite illuminating that the Catalogue of Ships in book 2 of the Iliad (there is general agreement that it was written at a later stage) has Ajax inserted in, as if to correct leaving him out in the first place. The existence of others such as Agamemnon, Odysseus, Achilles and others can be justified through similarly complicated means. This is of course all conjecture relying on the analysis of a poem, but it is very compelling.

There is further evidence, such as the tablets found at Pylos and the numerous other ruins of the Mycenaean citadels including Troy itself which was destroyed in a sack around the time that the Trojan war was meant to have happened.