Well, after some time of inaction (work work work), the last part of this AAR.
I captured all remaining ARS's and got spaceplanes and am now using them to search and destroy threat and important structures impeding the way to the homeworlds.
The other ARS yields microparasited which I'm not able to use effectively.
Meanwhile I sniped the Datacenters and coprocessors with transport and raid starships and brought the AIP back to the mark I level.
I then researched fortresses, sent my fleet in to clear and partially neuter the worlds surrounding the core worlds, taking care not to alert the core worlds themselves.
Both Pitlock and Yerabang are captured and several forresses and shipyards are positioned there to keep back the eventual counterattack when I assault the homeworld.
I now have a Hive and an Armored Golem and they are transported to Yerabang, since I finally learned how to use the teleporting leeches (I now have several caps worth of reclaimed ships guarding the whipping boy).
Several scouting parties are reduced to space dust, but the intel they collect on the core- and homesworlds reveals a nasty surprise: both accessable coreworlds and one of the homeworlds (Isioryo) have an AI Eye on them and since most of my fleet consists out of swarmers that is not good news.
I decide to destroy Xiasire first bring my fleet to the system ordering the core world.
After sniping the tachyon guardian with a few (caps) of missile frigates I send in the etherjets and spaceplanes and they slowly but surely destroy all the guardposts save one in the center because it's being protected by three Mk III fortresses, one of which destroys a complete strikeforce (Mk I II and III) of my spaceplanes trying to attack the guardpost inside ten seconds.
Enter the armored golem and it blasts the guardpost to bits in a few seconds, after which the Eye pops and the entire fleet charges in, carefully evading the central fortresses and going to the homeworld.
Having grown a bit impatient because of the slow progress I decide to attack the homeworld at one, not waiting to clear the Eye and quardposts first as it woudl probably take forever (6 million hitpoints ?!)
My fleet of about 3000 ships mostly low HP swarmers and the armored and hive golems charge in guns blazing.
That was a bad idea...
I don't know how the AI Eye determines the amount of zombies created, but I'm guessing it just keeps spawning them until they equal the attacking fleet in numbers.
So the amount of enemy ships goes up from about 250 to roughly 3500 (I did activate the hive golem when emerging from the wormhole) and they start coming towards me like a flock of locusts.
and start sending starships to kill the guardposts as quickly as possible while the AI is having my fleet or breakfast.
The forward bases start pouring out reinforcements, draining my economy dry at an alarming rate and finally the armored golem reaches the last quard post right next to the eye and pops it.
My siege starships (my new best friends) and a newly arrived bomber strike force start pounding the AI home command station and destroys it.
After the battle I review the damage:
1 hive golem severely damaged (retreated it "safely" to the core world at the beginning of the zombie onslaught and had to bring it back in because the reinforcements where attacking it)
1 armored golem at 2% hitpoints (this one saved the day).
About 2000 high cap fleet ships destroyed.
About 700 more expensive ships immoblilized by the two Ion cannons and those pesky anti-engine ships.
I start retreating as fast as possible as more reinforcements spawn through the weird wormhole but instead of attacking the immobilized fleet ships, they completely ignore them and go straight for the more valuable golems who barely make it to Yerabang moments before about a 100 Mk V's start engaging the fortresses.
Half an hour alter my fleet is rebuilt and the golems are back operational.
I decide to be more carefull this time and take no chances with the second coreworld (yep, also with an Eye on it), using the space planes to assasinate all guardposts.
The second homeworld proves a cakewalk
: my fleet simply storms in, annihilates all 200 mk V guards and breaks the AI core shield in minutes after the hive wasps kill all the guardposts.
Exactly an hour after I decided to attack I get my first look at that lovely "You Win" screen...
...and I start the next game.
Many thanks to all people on the forum for their helpfull tips and comments !
PS: seems I was actually wrong about the AI type being the Retaliatory AI, they were revealed to be the Vicious Raider and the Tag Teamer.