Q. 1. Who was the mother of Subhadra Maharani? Kindly tell me the lila of Subhadra Maharani being the sister of Lord Krishna.
Answer by Romapada Swami: Subhadra is the daughter of Vasudeva and Devaki. (Cf SB 10.1.56) For descriptions of lilas of Subhadra, you can use the vedabase link given below, particularly refer Canto 10, Ch 86 and also a summary description given in SB 1.13.3-4
Q. 2. Why is it that Srimati Radharani and Subadra Maharani do not wear tilak?
Answer by Romapada Swami: I have no answer as to why it is so, but tradition is that they wear bindis, not urdhva pundra tilaka.
From a conversation in 1972 with Srila Prabhupada:
Cintamani: Thank you. Krsna wears tilaka like we do, Srila Prabhupada?
Prabhupada: Yes. Radharani only red spot.