Misprounincing the letter ذ as ز , ظ or the letter ث as س , ص ?

Q: What about specifically misprounincing the letter ذ as ز , ظ or the letter ث as س , ص ? For non-arabs the letters ذ , ظ , and ث are quote difficult to pronounce since these letters are prounounced with a lisp i.e bringing the tongue between the upper and lower teeth when pronouncing it. So the non-arabs because they are not used to the lisp sound read the same representative lettersound without the lisp. In such case is the salaah invalid either intentionally or unintentionally?

Leaving out a Waajib in Salaah

Q: A salaah in which a wajib was left out, it is wajib to repeats within its time. But what if the time is over, is it still wajib to repeat it. Also such prayer can it be prayed at any time like after few days or is the order to pray it befor the next prayer obligatory? Do all makruh tahrimi acts, like omitting wajib, prayed with pictures on the cloth or towards a picture make it wajib to repeat the salaah? Or is it in some cases only sunnah or mustahab to repeat it?

Performing Salaah in a place where there are pictures of animate objects

Q: If one does after performance of salaah find a picture that would make his salaah makruh, is it still makruh since he was unaware of the picture or forgot completely to  cover it when he commenced the salaah? and what if he was unaware when he commenced the salaah, but during salaah he saw the picture or remembered he forgot to cover a picture? I assume in such cases there is no karahaat.

إفتتاح جزء قليل من عورة الرجل في الصلاة

س: لو وقع أثناء الصلاة إفتتاح جزء قليل من عورة الرجل، مثلا في حالة السجدة تحرك قميصه، و أدى ذلك إلى إفتتاح جزء قليل من عورة الرجل، و لكنه وقع بغير العمد و في وقت قليل (مثلا أثناء السجدة فقط). هل في الحالة المذكورة الصلاة - صحيحة؟

Performing Salaah next to a person who has a picture of an animate object on his clothing

Q: When arranging the row for prayer I saw that one man had a trouser with a PUMA logo (animation of a jaguar) at the side of the leg, so I did not stand next to him, but I stood next to the person who was standing next to him so that this animated picture would be not visible to me. However when we stood up for the 2nd rakah the man was for some seconds still in the sajdah posture so I saw this animated picture. Did my salaah become makruh and must I repeat it?