If he expects, although he may not be sure, to have sufficient time to offer the prayer completely in addition to performing the ghusl before it before sunrise, then he should do the ghusl and perform the prayer.If he anticipates that he has sufficient time to offer part of the prayer only before dawn after performing ghusl, then as an obligatory precaution he should perform the ghusl and offer the prayer even if some of it is after sunrise.If he realizes that he will not be able to offer any part of the prayer before sunrise, then it is better to perform the Tayammum and the prayer before sunrise, and then perform the Ghusl and repeat the prayer after sunrise.
Having sexual intercourse with your wife makes you in the state of janābah. It does not make your body najis. It makes the parts of your body that were in contact with semen najis only. If you made these parts tahir after the intercourse ends, then the entirety of your body is tahir. However, you are still required to perform the ghusl of janābah before offering the prayers. Therefore, you do not need to wash your clothes simply because you wore them when you were in the state of janābah, unless the semen or any other najasah came in contact with them.
Masturbation is prohibited at all times, and invalidates the fast if the semen is ejaculated. However, if he sees that it is permissible in the Sharia mistakenly then this does not invalidate the fast even if ejaculation takes place.
Males and females can pray in one row. However, it is better for the female to stand slightly behind the male in such a way that the place of prostration is level with the knee of the male when he is in prostration.