Doubting food

Q:

1. Is bread containing yeast halaal? Are foods assumed to be pure unless known or proven otherwise?

2. I have a lot of waswasa regarding every food, what should I do?

Buying expensive attars

Q: I want to buy attars that cost between R2000 and R4000 a bottle, but due to the high price, I fear it will displease Allah Ta'ala or it is not befitting of someone aspiring to be close to Allah Ta'ala. Is it fine for me to buy such attars? 

Meaning of the Hadith that the Jews and Christians will be burdened with the sins of the Muslims

Q: In the Qur'an, Allah said that no one will be burdened with the sins of another on the day of judgement but a hadith in Sahih Muslim said that the Jews and Christains will burdened with the sins of the Muslims on the day of judgement.

Abu Burdah (Radhiyallahu Anhu) reported the Messenger of Allah (Sallallahu Alaihi Wasallam) as saying: There would come people amongst the Muslims on the day of resurrection with sins heavy as a mountain and Allah would forgive them and he would place in their stead the Jews and Christains. Sahih muslim 2767d Sahih muslim, vol 6 , book of repentance, hadith 6668. 

Please clear this contradiction.