Firstly, you seem to have been mixed-up about the difference between galaxy and cosmos holo.It’s a bit confusing but:
-Galaxy holo = Star pattern (used in Base,Jg,Fossil,Legendary Collection)
-Cosmos holo = Dotted bubble pattern (used in Base 2 (the set released after fossil), Rocket,neo,etc)
-The Cosmos Holo Fossils is a variant/error/misprint that most collectors dont know exist due to not really appearing much but I believe its first documentation was by TCA gaming around 2013 and if memory serves me correctly, he obtained it from the Washington Seattle area. If you didnt know already, Washington Seattle is home to WOTC headquarters. Every source of these Fossil Cosmos seems to connect back to the Washington area which just cant be pure coincidence. I’m assuming your post about the cosmos foil muk is based on the recent $3250 ebay listing, and what do you know, the seller is based from Washington! If anyone reading this is from Seattle, perhaps have a look at your local card shops.
-About the zapdos you mentioned, a fossil zapdos with the cosmos holofoil with a 1999-2000 copyright came in these Thunderstorm gift box sets and hence its a fairly available card on the market. Thus if you ever see a 1999 copyright cosmos zapdos, thats is the rarer variant that comes from the cosmos holo fossil set.
-An additional misconception is that the cosmos holo fossils are related to the red-logo Australian print, which it is not. Holos pulled from red logo packs are your standard fossil unlimited holos with the galaxy foil.
-For further reading, here is a small guide i wrote up
www.elitefourum.com/t/rare-english-cosmos-fossil-holofoil-error-test-run-misprint/22232/1