Sajda-e-Sahw

Folding one's hands in the last rakaat of the sunnats of fajr while sitting and performing salaah

Q: If sitting down and performing sunnat of Fajr, after the last sajdah of the salah, one puts their hands up again for Surah Fatiha, but remembers before reciting anything, and then goes to continue tashahudd, should a qadha be recited for this salah? And should one have made sajdah sahw in such a case .

Imaam making a mistake in qiraat and remaining silent for more than three subhanallahs

Q: The imaan was reading Surah Sajdah. He got stuck repeatedly and paused for more then 3 subhanAllahs. Does salaah need to be repeated because he didn't make sijdah sahw? 

He got stuck like this before. He seems to be ignorant of the masla. 

He also stands with his legs far apart like a ghair muqalid. What should be done in this situation? How should he be corrected?