Re: The order of Rakahs in Salah
According to my knowledge and understanding: There is no Qiza for Sunah (Muqadah or gair-muqadah), nor there is end time. Qiza is only for Fard, because they are obligatory and should be done, even when time has passed.
Actually, we should understand that Sunnah is not fard (Sunnah is not obligatory). We do Sunnah because Prophet (SAW) used to do that. If one can understand that, answer to your question would become clear.
Prophet (SAW) prayed rikah before Fard Salah and also prayed rikah after Fard Salah (depending on particular Fard Salah). Praying rikah before Fard Salah with intention that one is following Prophet (SAW), than that would be considered as Sunnah. Rest of the rikah would be nafil. Same is true about rikah that one does after Fard Salah.
So, for a particular rikah to be valid as Sunnah, they have to be prayed according to what prophet (SAW) used to do, that is, before Fard Salah or after Fard Salah, as Prophet (SAW) did..
Now think yourself. Prophet (SAW) used to do 2 Rikah (we call that Sunnah) before 2 Rikah Fard Salah in Fajr.
If a person has not done those two rikah before fard (of fajr) and prayed fard, then he can do any number of rakah, even before fajr time ends or after, but certainly that would not be what Prophet (SAW) did … hence cannot be classified as Sunnan. Whatever the circumstances or intention (niyah), they would be nafil (as far as I know).
Same is true with Sunnah of Zuhar, that what should be done before Zuhar Frad Salah as Sunnah, cannot be done after Zuhar fard as Sunnah, regardless of time, circumstances, or intention. One can do 4 rikah Sunnah before fard, and 2 rikah sunnah after fard. Anything different, and they would not be Sunnah but would be Nafil,