Is fasting on consecutive days valid if a girl experiences a wet dream in Ramadan but does not perform ghusl, as she is not certain about the nature of the wetness and did not feel tremor or relaxation?

In summary: Purity from janabah (major ritual impurity) is not a condition for the validity of fasting. The mentioned discharges are either normal secretions or madhy (pre-seminal fluid). Even if there is a possibility that they are maniy (seminal fluid), ghusl (ritual bath) is not obligatory based on doubt regarding its cause. One may choose between considering it maniy or madhy when in doubt.