This is Sannyo's first Spellcard. It is based on the Kumomagusa flower, native to the mountains of Japan (Saxifraga Merkii, Fisch.)
Curiously, not all Kumomagusa have 6 overlapping pedals like Sannyo's, though some do. A spread out, 5 pedal variety is more common, though they are the same species, think of it as a 4 leaf clover vs 3 leaf, but not that rare. The overlapping 6 petal variety that Sannyo's Spellcard is modeled after is the mutated variety. (She does tend to go for the rare flowers, after all)
On the topic of variety, Kumomagusa also come in multiple colors beyond Sannyo's choice.
And it appears a "western style" one has been breed to survive in the west in different environments
Kumomagusa are a low perennial. Meaning they live for multiple years, but don't grow as tall as many perennial flowers tend to do.
Their natural habitat is generally stoney places that are well supplied with underground water in mountain regions.
like all of Sannyo's flowers, they are naturally extremely tough flowers and grow in rough environments.
Moving on to Sannyo's actual Spellcard, the variety she's chosen is a red edged, 6 petal Kumomagusa, evenly overlapped and with rounded petals
Here are some in game images for "Heaven Shaking Kumomagusa" the Spellcard's Normal mode version:
and here are some in game images for "Astonishing Kumomagusa". The Spellcard's Lunatic mode Version:
The pattern is extremely beautiful and recognizable, but it's not known for its difficulty.
Link to the art below:
(juwen971's stuff is awesome, they really like drawing Spellcards)
I believe this is the original text for Dual Vanish if you want to clear up any potentially misleading translations: スペルカード:時符「デュアルバニッシュ」時間を操り敵弾を現在、未来で二度消す。大量の得点アイテム(緑)が奪えるぞ I'm not denying your interpretation, but the "then the future" part strikes me as being more then just a simple vanishing act. Is Master Spark the only spellcard you wouldn't question the legitimacy of or is that also lacking sufficient evidence.
The relevant phrase here is 現在、未来で二度消す. As I expected, the verb is 消す (kesu), so you can’t really read too much into that. 二度 (nido) means “twice” as in the verb is happening on two separate occasions. 現在、未来 means “present, future” and yes the comma is a little grammatically odd, but in this case probably means “and”. で is a flexible little particle that can mean “on, in, at, by means of” etc. Basically で can only really be understood by context. Anyway, I would personally read that as “removes bullets in the present, and then removes bullets again in the future.” She’s explicitly “removing” the bullets twice, not simply removing the future bullets in the initial action.
It’s also worth noting that other than the brief “using time powers” at the start, the description is absolutely in terms of game mechanics. It goes on to talk about picking up items.
As for Master Spark, I believe Marisa shoots a big laser, but I don’t think the games necessarily convey the exact size and power of the laser, nor do they go into the mechanics of how it works. I’m not really sure what you mean by “legitimacy” though. As I said in the previous response, if we were taking everything at face value then Dual Vanish is explicitly an illusion, a misdirection, a trick. I believe that characters go out of their way to make their spellcards as cool as possible, since that’s the whole point really.