You know that you will be facing war elephants and heavy infantry. Against the former, you need priests. End of discussion. Therefore you need to get into the Bronze Age ASAP.
You are given massive amounts of stone, which is highly unusual, and gold, which is less unusual, and food and wood, of course. This bodes ill. Expect bad things to happen.
You start with 8 workers, including the fishing boats. Five of them can be put on food right away, one on stone, and one on gold. This leaves one to build some Houses, which are required immediately. You are going to need a flood of resources coming in, so the target is 20 workers, which means 12 new villagers, half at each Town Center to get them out as fast as possible. At the right TC, 2 collect food, 2 collect stone, 4 collect wood, and 2 build things. At the left TC, 2 collect gold, 1 builds things, and 5 collect food. Your initial production should be workers only.
Get the Scout moving right away. Leave the Scout Ships pretty much where they are; you don't want to be running into a bunch of Triremes. It's OK to explore the inner sea. You find out quickly that your base is separated into two parts, so that you need to have at least one Transport. The main part of your base is on the same landmass as the enemy base. Start building walls and Towers as soon as you reach your quota of workers.
Time passes. Your enemy is at 53 population, and might be static, but you know that they do have a bunch of villagers, and are collecting gold. Will they attack you? Everything seems to be peaceful when suddenly BOOM, Red war elephants and other nasty things land on your island, while your ships are being blown away by bigger ships. You should be using War Galleys by now, so at least they don't go down without a fight. How well you fare against the invasion depends strongly on whether you already have priests available or not. It is easy to lose 10 units in this first attack, but hopefully not more.
Replace all your ship casualties to maintain a fleet of 10 warships. Don't bother replacing your Tool Age units. Get some heavy infantry into play. Repair your Towers and walls and build some more of them. Keep sucking in the resources. Keep producing priests until you have 12. After a few more Red attacks, you should be stronger than you were before, having replaced all your casualties with equal or better units. It's time to get into the Iron Age.
Just keep building up. Keep beating off the attacks. Sink the enemy Transports on the way in if you can. It helps to physically block the inbound Transports. Line the shore with Towers; you certainly have enough stone. Keep a close eye on the mini-map, because you want to respond the instant a red dot shows up.
After a while, Pyrrhus gets tired of watching batches of troops sink to the bottom of the sea and switches to attacking with warships only. They do love their Catapult Triremes, but as you know, these don't stand up well in duels. Eventually, Pyrrhus gets tired of this, too. Detach one Trireme to explore the sea. Produce a couple of Catapult Triremes with the range upgrade, and start grinding away at the enemy Towers from the south. Expect resistance, although it is futile. You will be disbanding significant numbers of obsolete units, including villagers, by now. After all, 13 ships plus 12 priests plus 4 Phalanxes plus a handful of other useful troops does not leave room for 20 villagers.
Red has two docks. Don't destroy them yet. You may want to use them for trade gold, and you actually don't mind watching massive amounts of enemy resources going straight to the bottom of the sea.
When you get past the Red Towers in the south and start hitting Pyrrhus in his soft underbelly, he will send villagers to repair the damaged buildings. Kill them all. The AI is weak in this situation, because it does not leave a food reserve, and eventually it runs out of villagers, and then their economy shuts down, which means that they can't replace casualties. When you sense that you are in this regime, you should think about taking the fight to the enemy. There are many ways to do this, but the strongest is an all-priest attack. But because this will put you over the population limit, you need to prepare for it first.
You cannot reach much of the enemy base with your fleet, and you have good siege equipment, so produce a couple of catapults and a couple of Ballistae. Your cavalry is generally poor, so don't bother with any of those. Red doesn't have priests, so you won't need chariots. Start your assault when you have all the key units.
Load 4-6 priests in your Transport, plus a villager to repair the Transport. Start raiding the enemy coast. Bring a couple of warships along as escorts. Land your priests near a small group of enemy troops and assimilate them. If you put two priests on one unit, it can't fight back, but you need more priests to take on other responding units. Extract the converted unit, as well as the priests, with your Transport. There are several spots on the map where the priests can do their dirty work without having to worry about melee attack. Convert Heavy Horse Archers as a first priority. Once you have even three of them, you will be able to do a job on just about any enemy unit. Keep working the enemy army over with your priests, and there is no reason at all why you can't collect as many as 30 new recruits.
When Red has no army left, bring up your siege equipment and everybody else, really, and turn the Red city into dust.