Conditions for the validity of Salaah

Q: This morning I thought fajar happened around 6:35 so when I woke up around 6 I thought there was still time to pray. I went and made wudu and I am kind of sure that the sky was dark but there was like a very faint light when I started. I didn't think it was that late so I started praying. I struggle with OCD so it takes me a while to pray even four rakaat and when I was done the sky was still dark but it was a lighter blue colour. Did I pray at a forbidden time? Did my namaaz not count? I am so doubtful and my OCD makes everything so hard can you please tell me what I should do? If I have to repent or make it up do I read the prayer of repentance after making wudu?

Q: I have heard one is able to join prayer like zuhr and asr when need be. I am a student and I can never get any work done at home so I go to the library. Only the time between the two namazes are like three hours. Is it ok for me to join the two in this case because that gives me so much more time to sit there and get my work done?

Q: If I unintentionally make an intention of praying Asr fard Salaah instead of Zuhr and I realize that after the takbeer, then do I continue or break the Salaah?

Q: If you use clothing that has pictures with eyes and you cover it by wearing a jacket or jubbah, is your salaat valid?

Q: I read that using clothing with animate pictures are haram. Are we allowed to read salaah with a picture of an animal but it doesn't have the eyes drawn on it e.g. like a puma tracksuit pants?

Q:

1) If you pull up your pants to ensure that it remains above your ankles before going down for rukhu or sajda, does it break your salaat?

2) If your pants falls below your ankles while reading salaat, does it break your salaat?

3) If you perform salaat with your pants below the ankles, is your salaat valid?

4) what type of movements nullify salaat?

Q: If an imam recites the 1st 15 verses (i.e. 1st ruku) from (1-15) of Surah Maryam in his 1st rakaat of fajr salah and in his second rakat recites 25 verses (i.e 2nd ruku) from 16-40, is the salaah valid?

Q: Please advise if we can perform Asr Salaah in Shafi'ee time . This is done to accommodate staff that have transport problems and will not be able to make jamaat if Asr salaah is performed during hanafi time. Please advise.

Q: Is it permissible to perform Salaah with a short-sleeve kurta?

Q: If asr Salaah is until maghrib and if esha Salaah is until fajr, then why is there a hadith that says asr is until the sun turns yellow or pale and esha is until midnight?