I saw that someone had talked about timeline stuff a long while back and I just so happened to have a notepad timeline of events that happened pre-canon that I hadn't posted. I can't guarantee everything is correct here, and there are some useless/probably irrelevant facts about constellations and stars that I've noted within this list, and this isn't complete by any means, but here you go.
MAJOR SPOILERS BELOW THIS POINT.
ALSO: some of the dates here are majorly speculation, BUT the newspaper in the pandora kingdom explicitely read June 16th, 1965. That much is fact, at least in the anime.
- ~7895 b.c - Akai and Hoshi are stranded on earth.
- !!3942 b.c - Theta Draconis (Thuban) becomes nearest visible star to the celestial north pole.
- ~?????? time - Akai gifts Himiko the Urn of Life
- ~????? time - Akai and Hoshi get stuck in a cavern
- ~???? time - Akai and Hoshi are rescued from cavern by Aladdin, Akai grants Aladdin's wishes of money and status.
- !! ~3500 b.c - gem trade (lapis lazuli from mesopotamia region to egypt, Hoshi stuff probably straw that broke camel's back re: economy/trade issues.)
- ~3510-3520 b.c time (presumably within ten years of being sealed?) - Akai and Hoshi Wreck Egypt's Economy
- 3500 b.c - Akai and Hoshi are sealed in respective containers over in egypt area.
- ~248 ad??? maybe - Himiko dies x_x
- 1815 - Ichi exists, Travelling Jokers ep timeline interference.
- June 16th 1965 - Silver Heart is a secret agent, events of Pandora Kingdom transpire, stable timeloop goes here. (keystone of timeline)
- 1975 - Silver Heart steals the Blue Star from the Saffron kingdom.
- ~ 2000? - Queen's parents die, Queen Emerald/Diamond gets adopted/'stolen' by Silver Heart
- ~ ??? time - Jack's Parents die in plane crash.
- ~ 2005-6-ish??? - Jack gets taken in by Silver Heart
- ~ 2006-2007-ish????? - Spade goes along w/ Jack and Queen to become a phantom thief.
- ~ 2006-2008-ish : Cyan and Rose incident.
- ~ ??? time - Doubt escapes from lab, possibly with help of Clover
- ~2006-2008-ish : Roko escapes lab, starts training with trio?
Kaitou Joker present by time of Pandora ep before time travel bit: - June 16th 2015
if anyone has thoughts on all this, feel free to tell me!