What is the ruling on the discharge that comes out of an unmarried girl, which is thick and tends to be light yellowish or very light brownish with a yellowish tint, and does it necessitate ghusl or only wudu? And can semen be discharged hours after a wet dream and after ghusl, and what is the ruling on it if that is the case? And is it obligatory to re-perform the prayers in this situation?

If a woman is certain that what has exited from her is semen, then she must perform ghusl. If she is in doubt about it, then ghusl is not obligatory upon her; rather, she has a choice and can assign to it the ruling she wishes regarding what she doubted. It might be ordinary yellowish discharge that necessitates istinja' (washing private parts) and wudu' (ablution). Ghusl is not obligatory except with certainty that what has exited is semen. One should beware of waswas (whispers/obsessive thoughts). Prayers performed before the semen exited do not need to be repeated. Only those prayers performed after its exit without performing ghusl need to be repeated.