Salaah

Will a person who has two houses in different countries perform full salaah or qasar salaah?

Q: I lived in South africa for many years, then for some reason I moved to another country with my whole family. However, I still have my house in South Africa and I have the intention to come back and live in this house after a few years.

My question is that if I come to my house in South Africa for 3 days just to see if everything is alright, will I be a musaafir or not?

Imaam saying "samiallahu liman hamidah" instead of "Allah akbar" in salaah

Q:

1. In our college, the student imam, in between 2 sajdas forgetfully said, "SamiAllah huliman Hamida" instead of "Allahu Akbar", he did a 2-3 second pause and went for the second remaining sajda. The people behind him didn't even correct him but the second row guys had to correct him, by saying "Subhan Allah". After the completion of Salah, there was a big argument,

a. 3-4 people did sajda sahu after salah

b. The rest of the guys said "the Salah has to be repeated because the imam's niyyat is muqtadi's niyyat and if he makes mistake, it affects everybodys salah"

After that, the whole Salah was repeated by a different imaan. Who was right? a or b?

2. The imaam got up from ruku, and said "Allahu Akbar" instead of "SamiAllah huliman Hamida". The people behind him didn't correct him. The second row guys corrected him the wrong way, but this time by saying "SamiAllah huliman Hamida" instead of "Subhan Allah" and at the end, the imaam didn't even make sajda sahu. I have to repeat the Salah right? Because I have heard the imaam's niyyat is the muqtadi's niyyat and if he makes a mistake, it affects everybodys salah.