Actually I have been thinking the Time travel to Blackmoor events will need to occur before Synn the Night Dragon sucks up 5000 RAD of the Radiance. She will likely do this on Kladmont 28, AC1020: Day of Dread simply because where Wizard Magic Fails that Day, the Radiance (though the recepticle is enchanted like a magic item) is Artifact Based and therefor usable. It is the only Day she can do it without being attacked by other Wizards.That means Stephen and his green skinned buddies will need to be retrieved from the past in the year AC1020. It also means one of the Time-travelling PCs will need to be a Cleric of Benekander? Worse Still - what if this interferes with the eventual convergance of one of these Green Skinned fellows with an Elf Clan? Arnt the Aquerendi Green Skinned? What if they are Aquerendi simply because of the convergance of this 'Alien DNA' with an Elf clan?If these Green Skinned Aliens are the progenitors of the Green Skinned Aquerendi, perhaps the Aquerendi have a few Blackmoor Secrets? I'm thinking a Living Coral Starship under construction by some Aquerendi Cult to bring about a new age of access to Mystara Space.
Here is the Adventure suggestion for the Return of the Egg of Coot during the Modern age of Mystara
69. THE EGG RETURNS (AC1020) “I’ve almost got it.” Sedwik reached through the smashed-in hole and touched the two broken wires together. SYSTEMS ONLINE...RUNNING SYSTEMS CHECK. An indistinctive voice vibrated through the surface of the Giant Egg. DAMAGE DETECTED...AUTOREPAIR ACTIVATED. AUTOREPAIR WORKING...DAMAGE REPAIRED. Sedwik fell back from the egg as the damaged hole vanished. “Hello?” Sedwik reached out to touch the smooth stone. SENSORS ONLINE...SCANNING. SCAN COMPLETE...BIOLOGICAL PRESENCE DETECTED. ATTEMPTING TO MAKE CONTACT...ACCESSING LINGUISTIC PRIORITY LIST. GALACTIC-A: RESPOND PLEASE. “Anya! Come and listen to this...There is someone trapped inside it.” Sedwik felt about the surface looking for some catch to release the person trapped within. RESPONSE DETECTED...COMPARING...THONIAN VARIANT DETECTED. THONIAN: RESPOND PLEASE. “Anya! I think this egg just asked me to pleasure it!” Sedwik was shocked at the suggestion. RESPONSE DETECTED...COMPARING...AFRIDI VARIANT DETECTED. POSTULATING...ONE PERCENT THONIAN AND AFRIDI DETECTED IN SHARED SUBLANGUAGE. POSTULATING...A MINIMUM TWO THOUSAND YEARS HAVE ELAPSED. SUBDIALECT ALPHA: RESPOND EGG PLEASE. Anya the Witch listened to the Words... “You are right...The Egg just demanded you pleasure it. There must be some sort of evil Demon trapped within.” Sedwik backed away. “We must warn the Village Elders.” Anya nodded in agreement with Sedwik’s assessment of the Situation. DM BRIEFING: AN Earthquake and landslide exposes a previously burried Egg of Coot. Once reactivated in the Mystaran year AC1020 the Egg of Coot attempts to make contact with the Locals. Once it overcomes the language barrier it will attempt to teach them the Galactic Federation Language known as Galactic-A. Only then will it begin creating the new Age of Technology.