I think that if your tama is a V4, the easiest way to get a violetchi, is for your tama to be a female, and to have your teen be an ichigotchi or a young memetchi. If the flower points (social) are high enough, it should evolve into a violetchi! I'm going to aim for one, on my next generation! Well, on the V3s, V2s, and V1s I don't know how to get one. Well, hoped this helped anyone...let me know!
I did have one but I didn't. My friend Supergirltama (That is what she as known as on other websites.) went on holiday so I looked after her v2 since it was a teen and it grew into a Violetichi!