The jewel case tends to muddy the waters more than clarify anything, hilariously enough. The one exception I remember being DDC, as Sakuna's silhouette was pretty distinct. Apart from that, there have been some incredible attempts to find commonalities. Like I think one person noted a striking similarity between UFO's jewel case and Malmsteen's Fire and Ice album cover.
Yeah, I've been looking into previous game names, direct translations of the Japanese names, and jewel case combinations. The most confusing ones were probably IaMP and HM, although those are fighting games, so they don't really apply. The vaguest direct translated name is probably UFO's "Star Lotus Ship," the only relevant word being ship (while still being pretty useless).
Really, I've got a couple theories as to the plot of HSiFS, but the one that covers the translation name and the one that covers the english name don't really have any overlap, with the latter being all but ruled out. The "hidden star" could be anything, now that the chance of an eclipse messing with the weather has been tossed out and replaced with different weather in different areas. The Jade Scepter probably refers to either a Ruyi or a Shaku (not that I knew anything about either of those until I googled "japanese jade scepter"), but still that's kinda vague, other than shaku being used for Taoist and Shinto rituals, and Ruyi being used in Buddhism. There's also this thing
https://en.wikipedia.org/wiki/Gazu_Hyakki_Tsurezure_Bukuro (which I reached through the wikipedia page on Ruyi), which makes me think the final boss could be the tsukumogami of a ritual jade scepter. Who wants to mess with the weather. Because reasons. And something about a star. Unless the star is the extra stage boss, thus being "hidden." Hm, this seems to have circled around to the Extra-bosses-on-jewel-cases thing. Maybe it's too much to hope that it'll be like IN, where both the final and extra bosses were on the jewel case?
EDIT: Also, ZUN said that DDC started a new storyline in Gensokyo, just like how MoF did with Moriya shrine conspiracies. The final boss being a tsukumogami could be because of the Miracle Mallet in DDC.
ANOTHER EDIT: Expanding my above theory- thr final boss is the tsukumogami of a ritual jade scepter used to appease the storm god Susanoo. Now being a salty unused tsukumogami (because the outside world is turning from religion to science, blah blah MoF,) they decide to mess with the weather instead of fixing it. The extra stage boss ends up being a storm youkai, and Kogasa shows up in either the final or extra stage and ties with Nue on midboss appearances. The hidden star is... A simultaneous yet unrelated plot.
Okay, this is sounding a blazing hell of a lot like the fanmade game idea I had a couple weeks ago.
Finally, since LoLK revolved around the moon and HSiFS revolves around a star, the next game will end up being about the sun or something. Because sun/moon/stars. Insert Utsuho, Amaterasu, etc.