Imaamat and Jamaat Salaah for a Traveller

Q: I have a few questions regarding a musafir.

1. If a musafir joins the jamaat in the masjid, does he have to perform the full salaah? For example does he have to read the full 10 rakaats of Zohr or just the 4 Fardh that was read in jamaat?

2. Is it better to read the salaah in jamaat in the musjid or on my own, if I don't know any other musaafirs to make jamaat with?

3. Is it better to read qasr salaah or the full salaah when traveling, if I am reading alone?

Q: I was the imam in a salaah while travelling, a few other travellers also stopped, joined us and we performed salaah.

We had departed after Fajr, and had decided we will stop for Zohr at this location. After stopping we had meals etc. made wudhu and went to perform salaah.

At the time of starting the 2 rakaat jamaat salaah, I don't remember having a definite intention of performing Zohr Salah itself, although it was for this very reason we stopped. After saying the takbir the thought came into my mind that what salah am I performing? Is it Asr? Then I immediately realised no its Zohr.

After salaah I mentioned this to an alim there who said its fine, since we stopped for that very reason so "ilm" was evident, and "amal" as well was evident. When these two are found then this is sufficient, its not necessary to make the specific intention before salah.

1. Is this correct? Is the salah valid?

2. If it is invalid, what should one do when the musallis behind one cannot be traced?

Q: If a musaafir mistakenly leads a congregation in Zuhr Salaah for an entire week whilst performing 4 rakaats, and only realizes after that, then what is the status of the other musaafirs' Salaahs - those who performed salaah behind such an Imam?

Will their Salaah be valid/complete due to the passing of time?

Q:

1. If during traveling, an Imaam makes intention of qasr Asr but the muqtadi, who is also a traveler, mistakenly made intention of four rakaats. Will the muqtadi need to repeat the salaah (two rakaats qasr) or the niyyat of Imaam will be the one to supersede over that of the muqtadi and the muqtadi’s salaah behind the Imaam will be valid?

2. As a muqtadi, since I was not sure of the above, I repeated the Asr and prayed two rakaat qasr, was this action, in cases of doubts, correct until I come to know the right maslah?

Q: Can a musaafir pray in Masjid-e-Namirah and Masjid-e-Khair during hajj , as the imaam there offers only 2 rakaats irrespective of whether he is a muqeem or a musaafir as their madhab says to read only 2 rakaats during hajj?

Q: How can I do ishaa prayer if I am out of my city? After two rakats, should I do salam or should I wait until others complete their Prayer?

Q: A certain musaafir was following a muqeem in salaah and the musaafir was masbooq as well. However, he forgot about his missed rakaats and made salaam with the Imaam, and only remembered some time later that he did not perform the entire salaah. Should he make qadha of two rakaats or four rakaats?​

Q: A musaafir joined the zuhr salaah after the imam got up from ruku of the 4th rakaat. After the imam made salam the musaafir masbooq got up to complete his salah however he forgetfully read only 2 rakaats and made salam instead of completing 4 rakaats. Should he now repeat the whole 4 rakaats farz of zuhr or must he perform 2 rakaats qasr? 

Q:

1. If a Muqeem reads Salah behind a Musafir does he have to make intention for praying behind a Musafir?

2. If he makes intention of praying behind a Musafir whereas the Imam is a Muqeem, does he have to repeat the Salah?

3. What happens if a person reads a Surah in the 3rd Rakat of a Fardh Salah? Does it have to be repeated?

4. If two people read Salaah and the Musalli does not have Wudhu does the Imam have to repeat his Salah?

5. If two people are reading Salah and the Musalli by mistake makes intention of reading another Salah does the Imam have to repeat the Salaah?

6. If a person has missed a Salah whilst travelling and does Qadha at home does he have to read 2 or 4 Rakats?

Q: I would like to know the usool/adaab when travelling in a group and stop for salaah at a musjid where the salaah is almost finished. All the brothers in the group have wudhu but one brother doesn't have wudhu. Should all the brothers with wudhu join the jamaat leaving the one brother to miss salaah with jamaat, or should all wait for the brother making wudhu and perform another jamaat, or should most join the main jamaat and a few wait for the brother making wudhu and make another jamaat?