Lavandin essential oil, while similar to Lavender, is not a true lavender. It is a cross between lavender (Lavandula angustifolia) which grows at higher altitudes and spike lavender (Lavandula latifolia) which grows lower on the hillsides. It has a very sweet and floral aroma similar to "true" Lavender.
Melissa Essential Oil is steam distilled from the leaves and flowers of Melissa officinalis, an herb most commonly referred to as Lemon Balm and sometimes as Bee Balm. Lemon Balm is easy to find and grow. Although the leaves of Lemon Balm are quite aromatic, the leaves and flowers do not yield much essential oil.