Salaah

Q: In a answer i read that if someone forgets one of the shurut of salaah such as having wudhu, facing qibla,  and prays, then if he remembers before the time of that prayer expires it is fard to reap it, but if he remembers after the has expired it is mustahab to repeat. Please give your input.

Q: A person forgets to make sajdah sahw, is it wajib for him to repeat the salaah?

Q: I saw the following two hadith:

Our Nabi (Sallallaahu Alayhi wa-Sallam) said: "Do not forgo Salaah intentionally, lest you should get out of the fold of Islam. Do not perpetrate disobedience to Allah, lest you deserve His Wrath."

Rasulullah (Sallallaahu 'alayhi wa-Sallam) also said: "The dividing line between kufr and Imaan is Salaah." And : "A person who has missed one Salaah is like one who has lost all his family and wealth."

1. A person who misses salaah in its time but reads it later does he loose his imaan?
2. Is he still a muslim?

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?