No they were not, and you'll have trouble finding much about the "Sea Peoples" in general because they are something of a historical enigma. We have some very good, strong theories about who they might have been, but we don't have a real visual of their culture or even who all of them were. That said, the Sea Peoples are not nearly as mysterious as they once were, historians, linguists, and archaeologists have been chipping away at these questions for almost 200 years now. So what I can do is explain the origins of both the Sea Peoples and the Phoenicians on their own, and where they intersected.

The phrase "Sea Peoples" comes from Egyptian references to "Peoples of the Sea." These references primarily occur in narrative inscriptions of battle or conflicts from c. 1210-1150, from the reigns of Ramesses II to Ramesses III. Compiled from all of those inscriptions together the tribes listed are:

Denyen, Ekwesh, Karkisha, Lukka, Peleset, Shekelesh, Sherden, Teresh, Tjeker, Weshesh

The issue, of course, is that all of those names are Egyptian, and only a few of them correspond directly to other known tribes and locations in Egyptian/their neighbors ' records. Since the late 19th century, the primary theory has liked several of these tribes to different archaic names for Greek groups or tribes. Denyen to Danaoi and Ekwesh and Weshesh to Achaean. Meanwhile, Lukka and Peleset are easily identifiable as the Egyptian (and generally Semitic-language) names for the Lycians and Philistines, respectively. Other names are more contentious, and many have been linked to what appear to be Greek exonyms for other places, like connecting Teresh to "Tyrrhenian," a Greek name for Italic peoples. Of course, the Greeks must have gotten that name at some point, so maybe it was the Teresh. There is precedent for more western names associated with the Sea Peoples too, since Shekelesh and Sherden have been associated with Sicily and Sardinia.

It's the connection between the Sherden/Sardinia, Peleset/Philistines, and various Greeks that I want to emphasize. Immediately before the "Peoples of the Sea" start appearing in Egyptian records, the Mycenaean culture of Greece collapsed. Written language vanished from the Greek world for about 400 years, and populations shrank. Consequently, we have to guess there would have been mass displacement and we know that many Mycenaean Greeks settled elsewhere around this time.

One of those places seem to have been five major cities in the southern Levant that eventually became the Philistines of Biblical Fame. Especially in the early stages of Philistine settlement in the region, their material culture was distinct from the surrounding Canaanite peoples. Notably, it had a lot of characteristically Mycenaean features. For most of the last 150 years, it has been generally accepted, but unconfirmed that the Philistines, and thus the Peleset, were connected to Mycenaean Greece, and this provided the backbone for suggesting that the Sea Peoples were largely composed of Greeks in the wake of the Mycenaean collapse.

Well just last year, a genetic study on the Philistines revealed a lot of detail. While later Philistines were not significantly different from the surrounding peoples, the early Iron Age/late Bronze Age inhabitants of Ashkelon (the primary Philistine city) were genetically most connected to Greece and Sardinia. This isn't conclusive, and it's very new, but it lends a lot of credence to the connections of the Peleset to Greece, as well as the Sherden to both Greece and Sardinia (perhaps suggesting that another group of Mycenaeans ultimately settled in the west). Overall, it further supports the origins of "Sea Peoples" in Greece and Anatolia.

Meanwhile, I'm still supposed to tell you about the Phoenicians. They seem to be popular these days because I just answered a question about their connection to the ancient Israelites. To keep this wall of text a little shorter, I'll provide that one as reference because I also discuss the origins of the Phoenicians there. In short, the Phoenicians were the people who had always been there. They were a direct continuation of the Canaanite culture that existed during the Bronze Age. Historians begin referring to them by their Greek exonym in Iron Age histories for a variety of reasons, largely to do with the use of Greek sources for that period, and the condemnation of "Canaanites" in the Bible.

Now, we should still be careful not to present the Canaanite cultures as unscathed. They were actually capped off by the Sea Peoples a the north and south. Gaza and the other major sites of the south were taken by the Philistines as described above, and the wealthy city of Ugarit at the northern edge of Canaanite culture was completely destroyed by a seafaring invader around 1200. The cities that flourished in At home, the Hittite Empire was gone and Egypt had receded. The cities of the Levant were free from foreign domination and influence for a couple centuries. At sea, 1000 years of Mycenaean Greek and Minoan Crete domination of Aegean trade was over and the Phoenicians were able to fill the gap and facilitate the Mediterranean trade routes previously filled the culture that had suffered the greatest damage during the end of the Bronze Age.