Misplacing Zakaat money

Q: A friend of ours gave us his zakat money to send it to his other friend was in another country to distribute it there. When we contacted that foreign friend he said he doesn't know anyone so pls don't send me the money. The zakat giver had told us we can give to anyone else deserving. When we found someone suitable we realised we lost the money. We tried very hard to find it. It could be stolen. But we are not sure. What should we do. If we tell him he might get upset. Can we pay his zakat without telling him? Do we have to pay for him?

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.