Conditions for the validity of Salaah

Q: Is it permissible for one to join salaahs while travelling? I was informed that it is permissible and it is proven from the Ahaadith.

Q:

1. If I place a clean musalla on an impure carpet can I pray on that musalla?

2. Also, if I make wudhu and then stand with my wet feet on the musalla that is on the impure carpet will the musalla become impure since the water penetrates the musalla and goes to the carpet or will it be pure. Because I heard a masala that if you wrap a wet impure cloth inside another cloth the other cloth won't become impure.

Q: When is it permissible to join two salaahs; also what is the niyyat and method?

Q: On safr, is a person allowed to read asr in shafi asr time. If so, then since a hanafi's zuhr ends at asr hanafi, can a person still read zuhr in asr shafi time and after a few minutes read the asr salaah?

Q: My grandmother finds it difficult to stay awake after maghrib. Is it ok if she reads esha with her tahajjud?

Q: Is it permissible to pray wearing shoes? Because I've read a hadith that it is permissible so I just wanted to clarify it.

Q: If a person is still praying one salaah when the time for the next salaah enters, e.g. they are in the middle of praying Asr when Maghrib enters, is that salaah valid or do they have to make it up afterwards?

Q: I got home a little late from college and there was little time left for Maghrib but I prayed it anyway and got a little into Esha time. Was it wrong for me to pray Maghrib knowing it was about to be over? Should I pray anyway if a situation like this occurs?

Q: Mufti sahab, After I read Asr Fard Salaah, can I read any nawaafil Salah or any qadha fardh salaah?

Q: When I pray namaz, in the starting I read niyat in urdu for e.g: (I do niyat to perform 4 rakats isha facing towards the qibla). Is this the correct way to start namaz or should we just start with Allahu akbar?