A: I'm glad someone caught it. When "Might" is used, that means it's Effective Might (143.2.a.1.), which is then only applicable to the Arithmetic layer (479.4.a.). If we were to follow this literal interpretation, it means Blossoming could be 4 + 2 = 6[M].
However, it seems quite obvious that is unintentional and it makes more sense that Orianna is only meant to modify Base Might in the Trait-Altering layer (479.2.a.). Thankfully, we do not have Blue/Green cards that set Base Might, but hopefully she gets future-proofed with an errata if such cards are printed.
Interesting. Since there's no printed base might on the gear and Orianna's ability doesn't say "base might" it wouldn't be too far-fetched to say 6. Curious to see how it works under the current rules.