I don't know where the mess-up could have been. They have picked bad VAs, before, like when they had the VA do an old women's voice for the young teacher in the first season. It may have been intended to be female in the Japanese dub of the show and that's where SA got he info and made Wilda a female on their sight…
here is what i think is the relation between vandarus and wilda.You know the viper helios spectra has is all black and the same thing happened when he got ahold of drago.It could be the same with mira.When she betrayed the resistance she then turn evil after spectra like ruins her mind.After that since mira turned evil wild turns evil and becomes vandarus with a some black designs like on spectra's viper helios.
I like the idea of Wilda-Vandarus when controlled by the vexos. Mira lost to Spectra-ep 21-and she is now a vexo. Wilda might be transformed into Vandarus.
My new idea:After becoming a Vexos, Wilda becomes upgraded into Vandarus, and Baliton into Hexstar. Believe that or not, Wilda will not, nor has he, evolve/evolved into/from Vandarus.