Qiraat

Reciting a portion of one surah in the first rakaat and reciting a portion of another Surah in the second rakaat

Q: If a person recites from the middle of one surah in one rakaat and from the middle of another surah in the second rakaat or if a person recites from the end of one surah in one rakaat and from the end of another surah in the second rakaat of a fardh Salaah, will the Salaah be valid?

Taking a breath after every Aayat

Q:

1. When reciting surahs in salaah, does one have to t​ake a breath after every verse or can they just pause slightly and go onto next verse.

2. What if they stop and take a breath on a part they should not and carry on reading. Like in Surah Fatiha, I sometimes take a breath just before 'ghair ril maghdoobi alaihim' even though there is no pause there. Is my Salah ok in both cases?