I think u may use thick-skinned in the meaning of หน้าด้าน ... The meaning of its Janee explained above.
In addition, big-faced also has the meaning in Thai. big-faced = หน้าใหญ่ (Naa yai) is a behavior of someone who always give money, kindness, etc., more than usual or expected. Seem likes Generous i guess.
For Snake in the head, i think one nice description is, elder playboy.