Okay, so I did the Tunguska Epilogue and to get the brass tacks out of the way:
- U-Olga Marie is capable of seeing even molecules(She calls it "Omnipotent Sight") but it also shows why she nor anyone else could find the Wandering Sea till she actually tried(And apparently found it in 3 seconds and considering we see Fou was staring at the ceiling since the Storm Border came back, she isn't lying).
- So I was already wrong about the function of the "Gates" lol... sorta. They are based on the Mages who are behind the Gates but in truth, they are actual Time Gates as the True Wandering Sea doesn't actually exist at all in Space Time(Fabro states it's completely shunted out of the Universe) and what Chaldea and Sion used as a base is just a Shadow of it the entire time. Even if that's destroyed, it's only destroyed in that timeframe(Basically the Wandering Sea is destroyed in 2019 but it does not mean it's destroyed altogether and still exists as it's acausal in a sense), this also means that The True Wandering Sea is able to see all of the timelines(As Fabro basically calls FGO Sion The Dust of Osiris, someone who only exists in the Melty Blood Timeline)
- In order for Fabro to even come back to the present timeline, he needed enough Magical Energy to destroy a Continent(LMFAO, Nasu and Albert, you sly fucks) and his mentor allowed him to do it as in his own words "They had no use for that amount of Magical Energy left over". And yeah, Fabro is "Modern" by the standards of the Mages in the True Wandering Sea
- The fan translation spoilers are correct in that Sion hit U-Olga Marie with the Wandering Sea before it was destroyed by the Pseudo-Black Hole, what they didn't really mention(maybe outside of the Beast Lair translation) is that Sion actually compressed the entire island the smallest she could and flung it into U-Olga Marie(Meaning that she was basically hit by an equivalent of a High Density Gravitational attack, atleast if I remember the concept of compressing something huge into something really small without losing it's mass right).
I can go back and look at the notes in case I screwed up or messed something up important(Especially with the True Wandering Sea, it comes off like a legit headache like the Moon Cell already) but I tried.